Targeting NK Cells to Enhance Melanoma Response to Immunotherapies

NKG2D ligand expression on NK cells induces NKG2D-mediated cross-tolerization of cytokine signaling and reduces NK cell tumor immunity

Studies support a role for natural killer (NK) cells in cancer control, making these cells attractive for immunotherapy. One method being tested to make effective NK cells is the ex vivo activation with interleukin (IL)-12, IL-15, and IL-18. We demonstrate that this induces NKG2D ligands on NK cells. By engaging NKG2D, this NKG2D ligand expression eliminated the ability of both mouse and human NK cells to control tumor growth in vivo and in vitro, respectively. NKG2D-NKG2D ligand interaction between mouse NK cells reduced NK cell proliferation, CD25 and T-bet expression, and tumor necrosis factor and interferon γ release. NKG2D signaling induced between human NK cells similarly decreased interferon γ but did not affect T-bet or CD25 expression. These data demonstrate that NKG2D signaling can cross-tolerize cytokine signaling and suggest that eliminating this signaling could be beneficial in NK cell adoptive therapy. Further, these results highlight a need to better delineate effects downstream of NKG2D signaling in human, rather than mouse, NK cells.

Application of adoptive cell therapy in malignant melanoma

Cutaneous melanoma is one of the most aggressive skin cancers originating from skin pigment cells. Patients with advanced melanoma suffer a poor prognosis and generally cannot benefit well from surgical resection and chemo/target therapy due to metastasis and drug resistance. Thus, adoptive cell therapy (ACT), employing immune cells with specific tumor-recognizing receptors, has emerged as a promising therapeutic approach to display on-tumor toxicity. This review discusses the application, efficacy, limitations, as well as future prospects of four commonly utilized approaches -including tumor-infiltrating lymphocytes, chimeric antigen receptor (CAR) T cell, engineered T-cell receptor T cells, and chimeric antigen receptor NK cells- in the context of malignant melanoma.

The role of immunity in insulin resistance in patients with polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is a prevalent disorder of the endocrine system with significant clinical implications, often leading to health complications related to adipose tissue accumulation, including obesity, insulin resistance (IR), metabolic syndrome, and type 2 diabetes mellitus. While the precise pathogenesis of PCOS remains unclear, it is now recognized that genetic, endocrine, and metabolic dysregulations all contribute significantly to its onset. The immunopathogenesis of PCOS has not been extensively explored, but there is growing speculation that immune system abnormalities may play a pivotal role. This chronic inflammatory state is exacerbated by factors such as obesity and hyperinsulinemia. Therefore, this review aims to elucidate the interplay between IR in PCOS patients, the controlled immune response orchestrated by immune cells and immunomodulatory molecules, and their interactions with adipocytes, hyperandrogenemia, chronic inflammation, and metabolic homeostasis.

The Rational Engineered Bacteria Based Biohybrid Living System for Tumor Therapy

Living therapy based on bacterial cells has gained increasing attention for their applications in tumor treatments. Bacterial cells can naturally target to tumor sites and active the innate immunological responses. The intrinsic advantages of bacteria attribute to the development of biohybrid living carriers for targeting delivery toward hypoxic environments. The rationally engineered bacterial cells integrate various functions to enhance the tumor therapy and reduce toxic side effects. In this review, the antitumor effects of bacteria and their application are discussed as living therapeutic agents across multiple antitumor platforms. The various kinds of bacteria used for cancer therapy are first introduced and demonstrated the mechanism of antitumor effects as well as the immunological effects. Additionally, this study focused on the genetically modified bacteria for the production of antitumor agents as living delivery system to treat cancer. The combination of living bacterial cells with functional nanomaterials is then discussed in the cancer treatments. In brief, the rational design of living therapy based on bacterial cells highlighted a rapid development in tumor therapy and pointed out the potentials in clinical applications.

Innate immune cells in tumor microenvironment: A new frontier in cancer immunotherapy

Innate immune cells, crucial in resisting infections and initiating adaptive immunity, play diverse and significant roles in tumor development. These cells, including macrophages, granulocytes, dendritic cells (DCs), innate lymphoid cells, and innate-like T cells, are pivotal in the tumor microenvironment (TME). Innate immune cells are crucial components of the TME, based on which various immunotherapy strategies have been explored. Immunotherapy strategies, such as novel immune checkpoint inhibitors, STING/CD40 agonists, macrophage-based surface backpack anchoring, ex vivo polarization approaches, DC-based tumor vaccines, and CAR-engineered innate immune cells, aim to enhance their anti-tumor potential and counteract cancer-induced immunosuppression. The proximity of innate immune cells to tumor cells in the TME also makes them excellent drug carriers. In this review, we will first provide a systematic overview of innate immune cells within the TME and then discuss innate cell-based therapeutic strategies. Furthermore, the research obstacles and perspectives within the field will also be addressed.

Morphological and Immunohistochemical Aspects with Prognostic Implications and Therapeutic Targets of Primary Sinonasal Mucosal Melanoma: A Retrospective Study

Sinonasal mucosal melanoma originates from melanocytes and it is a rare malignancy in the sinonasal tract. It is an aggressive melanocytic neoplasm with a very poor prognosis. The symptoms are nonspecific and the diagnosis is delayed, usually until the advanced stages of the disease. The current study performs a correlation between the histopathological aspects of sinonasal mucosal melanoma and different types of immune cells present in the microenvironment, with prognostic and therapeutic implications. The endpoint is to quantify the cellular immune microenvironment and correlate it with patient survival. This study presents nine cases of primary sinonasal mucosal melanomas diagnosed at the Emergency City Hospital Timisoara, Romania during a period of 15 years. The histopathological examination was performed in the Department of Pathology of the same hospital, using morphological hematoxylin-eosin staining. Additional immunohistochemical reactions were performed to confirm the diagnosis and evaluate the components of the tumor immune microenvironment. This study identifies eosinophils, macrophages, natural killer cells and plasma cells as favorable prognostic factors. Therefore, a CD8:CD4 ratio of more than 3 is correlated with a good response to PD-1 inhibitor therapy.

Beyond Immune Checkpoint Inhibitors: Emerging Targets in Melanoma Therapy

PURPOSE OF REVIEW

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

RECENT FINDINGS

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

Determinants of resistance and response to melanoma therapy

Metastatic melanoma is among the most enigmatic advanced cancers to clinically manage despite immense progress in the way of available therapeutic options and historic decreases in the melanoma mortality rate. Most patients with metastatic melanoma treated with modern targeted therapies (for example, BRAFV600E/K inhibitors) and/or immune checkpoint blockade (for example, anti-programmed death 1 therapy) will progress, owing to profound tumor cell plasticity fueled by genetic and nongenetic mechanisms and dichotomous host microenvironmental influences. Here we discuss the determinants of tumor heterogeneity, mechanisms of therapy resistance and effective therapy regimens that hold curative promise.

The role of PD-1/PD-L1 signaling pathway in cancer pathogenesis and treatment: a systematic review

Aim: Cancer as a complex disease poses significant challenges for both diagnosis and treatment. Researchers have been exploring various avenues to find effective therapeutic strategies, with a particular emphasis on cellular signaling pathways and immunotherapy. One such pathway that has recently been suggested is the PD-1/PD-L1 pathway, which is an immune checkpoint signaling system that plays an important role in regulating the immune system and maintaining tissue homeostasis. Cancer cells exploit this pathway by producing PD-L1, which attaches to PD-1 on T cells, thus inhibiting immune responses and enabling the cancer cells to escape detection by the immune system. This study aimed to evaluate the role of the PD-1/PD-L1 pathway in cancer pathogenesis and treatment. Method: This study was performed based on the principles of Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA). All in vitro , in vivo , and clinical studies that were published in English have been considered during a thorough search of the Scopus, Web of Science, and PubMed databases without date restriction until March 2024. Results: According to the studies reviewed, the PD-1/PD-L1 signaling axis suggests promising therapeutic effects on various types of cancers such as non-small cell lung cancer, melanoma, breast cancer, hepatocellular carcinoma, squamous cell carcinoma, and colorectal cancer, among others. Additionally, research suggests that immune checkpoint inhibitors that block PD1/PD-L1, such as pembrolizumab, atezolizumab, nivolumab, durvalumab, cemiplimab, avelumab, etc. , can effectively prevent tumor cells from escaping the immune system. Moreover, there might be a possible interaction between microbiome, obesity, etc. on immune mechanisms and on the immune checkpoint inhibitors (ICIs). Conclusion: Although we have gained considerable knowledge about ICIs, we are still facing challenges in effectively prescribing the appropriate ICIs for individual patients. This is largely due to the complex interactions between different intracellular pathways, which need to be thoroughly studied. To resolve this issue, it is necessary to conduct more reliable clinical trials that can produce a scientific consensus.

Tumor-infiltrating lymphocytes as a prognostic and predictive factor for Melanoma

INTRODUCTION

Tumor-infiltrating lymphocytes (TILs) have been investigated as prognostic factors in melanoma. Recent advancements in assessing the tumor microenvironment in the setting of more widespread use of immune checkpoint blockade have reignited interest in identifying predictive biomarkers. This review examines the function and significance of TILs in cutaneous melanoma, evaluating their potential as prognostic and predictive markers.

AREAS COVERED

A literature search was conducted on papers covering tumor infiltrating lymphocytes in cutaneous melanoma available online in PubMed and Web of Science from inception to 1 December 2023, supplemented by citation searching. This article encompasses the assessment of TILs, the role of TILs in the immune microenvironment, TILs as a prognostic factor, TILs as a predictive factor for immunotherapy response, and clinical applications of TILs in the treatment of cutaneous melanoma.

EXPERT OPINION

Tumor-infiltrating lymphocytes play a heterogeneous role in cutaneous melanoma. While they have historically been associated with improved survival, their status as independent prognostic or predictive factors remains uncertain. Novel methods of TIL assessment, such as determination of TIL subtypes and molecular signaling, demonstrate potential for predicting therapeutic response. Further, while their clinical utility in risk-stratification in melanoma treatment shows promise, a lack of consensus data hinders standardized application.

Therapeutic approaches to enhance natural killer cell cytotoxicity

Enhancing the cytotoxicity of natural killer (NK) cells has emerged as a promising strategy in cancer immunotherapy, due to their pivotal role in immune surveillance and tumor clearance. This literature review provides a comprehensive overview of therapeutic approaches designed to augment NK cell cytotoxicity. We analyze a wide range of strategies, including cytokine-based treatment, monoclonal antibodies, and NK cell engagers, and discuss criteria that must be considered when selecting an NK cell product to combine with these strategies. Furthermore, we discuss the challenges and limitations associated with each therapeutic strategy, as well as the potential for combination therapies to maximize NK cell cytotoxicity while minimizing adverse effects. By exploring the wealth of research on this topic, this literature review aims to provide a comprehensive resource for researchers and clinicians seeking to develop and implement novel therapeutic strategies that harness the full potential of NK cells in the fight against cancer. Enhancing NK cell cytotoxicity holds great promise in the evolving landscape of immunotherapy, and this review serves as a roadmap for understanding the current state of the field and the future directions in NK cell-based therapies.

An AI-assisted integrated, scalable, single-cell phenomic-transcriptomic platform to elucidate intratumor heterogeneity against immune response

We present a novel framework combining single-cell phenotypic data with single-cell transcriptomic analysis to identify factors underpinning heterogeneity in antitumor immune response. We developed a pairwise, tumor-immune discretized interaction assay between natural killer (NK-92MI) cells and patient-derived head and neck squamous cell carcinoma (HNSCC) cell lines on a microfluidic cell-trapping platform. Furthermore we generated a deep-learning computer vision algorithm that is capable of automating the acquisition and analysis of a large, live-cell imaging data set (>1 million) of paired tumor-immune interactions spanning a time course of 24 h across multiple HNSCC lines (n = 10). Finally, we combined the response data measured by Kaplan-Meier survival analysis against NK-mediated killing with downstream single-cell transcriptomic analysis to interrogate molecular signatures associated with NK-effector response. As proof-of-concept for the proposed framework, we efficiently identified MHC class I-driven cytotoxic resistance as a key mechanism for immune evasion in nonresponders, while enhanced expression of cell adhesion molecules was found to be correlated with sensitivity against NK-mediated cytotoxicity. We conclude that this integrated, data-driven phenotypic approach holds tremendous promise in advancing the rapid identification of new mechanisms and therapeutic targets related to immune evasion and response.

GMP-Based Isolation of Full-Term Human Placenta-Derived NK Cells for CAR-NK Cell Therapy in Malignant Melanoma

Melanoma, a severe type of skin cancer, poses significant management challenges due to its resistance to available treatments. Despite this obstacle, the high immunogenicity of melanoma renders it amenable to immune therapy, and NK cells have been identified as possessing anti-tumor properties in immunotherapy. The development of chimeric antigen receptor (CAR)-modified NK cells, or CAR-NK cells, has shown potential in enhancing immunotherapeutic regimens. To achieve this, researchers have explored various sources of NK cells, including those derived from the placenta, which offers benefits compared to other sources due to their limited ex vivo expansion potential. Recent studies have indicated the capacity to expand functional NK cells from placenta-derived cells in vitro that possess anti-tumor cytolytic properties. This chapter discusses the isolation of full-term human placenta-derived NK cells using Good Manufacturing Practice-based methods for CAR-NK cell therapy in melanoma.

The nexus of natural killer cells and melanoma tumor microenvironment: crosstalk, chemotherapeutic potential, and innovative NK cell-based therapeutic strategies

The metastasis of melanoma cells to regional lymph nodes and distant sites is an important contributor to cancer-related morbidity and mortality among patients with melanoma. This intricate process entails dynamic interactions involving tumor cells, cellular constituents, and non-cellular elements within the microenvironment. Moreover, both microenvironmental and systemic factors regulate the metastatic progression. Central to immunosurveillance for tumor cells are natural killer (NK) cells, prominent effectors of the innate immune system with potent antitumor and antimetastatic capabilities. Recognizing their pivotal role, contemporary immunotherapeutic strategies are actively integrating NK cells to combat metastatic tumors. Thus, a meticulous exploration of the interplay between metastatic melanoma and NK cells along the metastatic cascade is important. Given the critical involvement of NK cells within the melanoma tumor microenvironment, this comprehensive review illuminates the intricate relationship between components of the melanoma tumor microenvironment and NK cells, delineating their multifaceted roles. By shedding light on these critical aspects, this review advocates for a deeper understanding of NK cell dynamics within the melanoma context, driving forward transformative strategies to combat this cancer.

CAR NK Cell Therapy for the Treatment of Metastatic Melanoma: Potential & Prospects

Melanoma is among the most lethal forms of cancer, accounting for 80% of deaths despite comprising just 5% of skin cancer cases. Treatment options remain limited due to the genetic and epigenetic mechanisms associated with melanoma heterogeneity that underlie the rapid development of secondary drug resistance. For this reason, the development of novel treatments remains paramount to the improvement of patient outcomes. Although the advent of chimeric antigen receptor-expressing T (CAR-T) cell immunotherapies has led to many clinical successes for hematological malignancies, these treatments are limited in their utility by their immune-induced side effects and a high risk of systemic toxicities. CAR natural killer (CAR-NK) cell immunotherapies are a particularly promising alternative to CAR-T cell immunotherapies, as they offer a more favorable safety profile and have the capacity for fine-tuned cytotoxic activity. In this review, the discussion of the prospects and potential of CAR-NK cell immunotherapies touches upon the clinical contexts of melanoma, the immunobiology of NK cells, the immunosuppressive barriers preventing endogenous immune cells from eliminating tumors, and the structure and design of chimeric antigen receptors, then finishes with a series of proposed design innovations that could improve the efficacy CAR-NK cell immunotherapies in future studies.

The molecular perspective on the melanoma and genome engineering of T-cells in targeting therapy

Melanoma, an aggressive malignant tumor originating from melanocytes in humans, is on the rise globally, with limited non-surgical treatment options available. Recent advances in understanding the molecular and cellular mechanisms underlying immune escape, tumorigenesis, drug resistance, and cancer metastasis have paved the way for innovative therapeutic strategies. Combination therapy targeting multiple pathways simultaneously has been shown to be promising in treating melanoma, eliciting favorable responses in most melanoma patients. CAR T-cells, engineered to overcome the limitations of human leukocyte antigen (HLA)-dependent tumor cell detection associated with T-cell receptors, offer an alternative approach. By genetically modifying apheresis-collected allogeneic or autologous T-cells to express chimeric antigen receptors, CAR T-cells can appreciate antigens on cell surfaces independently of major histocompatibility complex (MHC), providing a significant cancer cell detection advantage. However, identifying the most effective target antigen is the initial step, as it helps mitigate the risk of toxicity due to "on-target, off-tumor" and establishes a targeted therapeutic strategy. Furthermore, evaluating signaling pathways and critical molecules involved in melanoma pathogenesis remains insufficient. This study emphasizes the novel approaches of CAR T-cell immunoediting and presents new insights into the molecular signaling pathways associated with melanoma.

Tumor-Infiltrating iNKT Cells Activated through c-Kit/Sca-1 Are Induced by Pentoxifylline, Norcantharidin, and Their Mixtures for Killing Murine Melanoma Cells

The involvement of NK and other cytotoxic cells is considered the first defense line against cancer. However, a significant lack of information prevails on the possible roles played by factors considered characteristic of primitive cells, such as c-kit and Sca-1, in activating these cells, particularly in melanoma models subjected to treatments with substances under investigation, such as the case of norcantharidin. In this study, B16F1 murine melanoma cells were used to induce tumors in DBA/2 mice, estimating the proportions of NK and iNKT cells; the presence of activation (CD107a+) and primitive/activation (c-kit+/Lya6A+) markers and some tumor parameters, such as the presence of mitotic bodies, nuclear factor area, NK and iNKT cell infiltration in the tumor, infiltrated tumor area, and infiltrating lymphocyte count at 10x and 40x in specimens treated with pentoxifylline, norcantharidin, and the combination of both drugs. Possible correlations were estimated with Pearson's correlation analysis. It should be noted that, despite having demonstrated multiple correlations, immaturity/activation markers were related to these cells' activation. At the tumor site, iNKT cells are the ones that exert the cytotoxic potential on tumor cells, but they are confined to specific sites in the tumor. Due to the higher number of interactions of natural killer cells with tumor cells, it is concluded that the most effective treatment was PTX at 60 mg/kg + NCTD at 0.75 mg/kg.

Lymph node metastasis and tumor-educated immune tolerance: Potential therapeutic targets against distant metastasis

Lymph node metastasis has been shown to positively associated with the prognosis of many cancers. However, in clinical treatment, lymphadenectomy is not always successful, suggesting that immune cells in the tumor and sentinel lymph nodes still play a pivotal role in tumor immunosuppression. Recent studies had shown that tumors can tolerate immune cells through multiple strategies, including tumor-induced macrophage reprogramming, T cells inactivation, production of B cells pathogenic antibodies and activation of regulatory T cells to promote tumor colonization, growth, and metastasis in lymph nodes. We reviewed the bidirectional effect of immune cells on anti-tumor or promotion of cancer cell metastasis during lymph node metastasis, and the mechanisms by which malignant cancer cells modify immune cells to create a more favorable environment for the growth and survival of cancer cells. Research and treatment strategies focusing on the immune system in lymph nodes and potential immune targets in lymph node metastasis were also be discussed.

Targeting Potential of Innate Lymphoid Cells in Melanoma and Other Cancers

Reinvigorating the killing function of tumor-infiltrating immune cells through the targeting of regulatory molecules expressed on lymphocytes has markedly improved the prognosis of cancer patients, particularly in melanoma. While initially thought to solely strengthen adaptive T lymphocyte anti-tumor activity, recent investigations suggest that other immune cell subsets, particularly tissue-resident innate lymphoid cells (ILCs), may benefit from immunotherapy treatment. Here, we describe the recent findings showing immune checkpoint expression on tissue-resident and tumor-infiltrating ILCs and how their effector function is modulated by checkpoint blockade-based therapies in cancer. We discuss the therapeutic potential of ILCs beyond the classical PD-1 and CTLA-4 regulatory molecules, exploring other possibilities to manipulate ILC effector function to further impede tumor growth and quench disease progression.

Immunomodulatory Function of Interleukin-15 and Its Role in Exercise, Immunotherapy, and Cancer Outcomes

Exercise has been shown to improve physical and psychosocial outcomes for people across the cancer care continuum. A proposed mechanism underpinning the relationship between exercise and cancer outcomes is exercise-induced immunomodulation via secretion of anti-inflammatory myokines from skeletal muscle tissue. Myokines have the potential to impair cancer growth through modulation of natural killer (NK) cells and CD8+ T cells while improving the effectiveness of cancer therapies. Interleukin-15 (IL-15), one of the most abundant myokines found in skeletal muscle, has a key immunoregulatory role in supporting the proliferation and maturation of T cells and NK cells, which have a key role in the host's immune response to cancer. Furthermore, IL-15 is being explored clinically as an immunotherapy agent with doses similar to the IL-15 concentrations released by skeletal muscle during exercise. Here we review the role of IL-15 within the immune system, examine how IL-15 is produced as a myokine during exercise, and how it may improve outcomes for people with cancer, specifically as an adjuvant or neoadjuvant to immunotherapy. We summarize the available evidence showing changes in IL-15 in response to both acute exercise and training, and the results are inconsistent; higher quality research is needed to advance the understanding of how exercise-mediated increases in IL-15 potentially benefit those who are being treated for, or who have had, cancer.

P2X7 receptor activation impairs antitumour activity of natural killer cells

BACKGROUND AND PURPOSE

A high number of intratumoural infiltrating natural killer (NK) cells is associated with better survival in several types of cancer, constituting an important first line of defence against tumours. Hypoxia in the core of solid tumours induces cellular stress and ATP release into the extracellular space where it triggers purinergic receptor activation on tumour-associated immune cells. The aim of this study was to assess whether activation of the purinergic receptor P2X7 by extracellular ATP plays a role in the NK cells antitumour activity.

EXPERIMENTAL APPROACH

We carried out in vitro experiments using purified human NK cells triggered through P2X7 by extracellular ATP. NK cell killing activity against the tumour target cells K562 was studied by means of NK cytotoxicity assays. Likewise, we designed a subcutaneous solid tumour in vivo mouse model.

KEY RESULTS

In this study we found that human NK cells, expressing a functional plasma membrane P2X7, acquired an anergic state after ATP treatment, which impaired their antitumour activity and decreased IFN-γ secretion. This effect was reversed by specific P2X7 antagonists and pretreatment with either IL-2 or IL-15. Furthermore, genetic P2rx7 knockdown resulted in improved control of tumour size by NK cells. In addition, IL-2 therapy restored the ability of NK cells to diminish the size of tumours.

CONCLUSIONS AND IMPLICATIONS

Our results show that P2X7 activation represents a new mechanism whereby NK cells may lose antitumour effectiveness, opening the possibility of generating modified NK cells lacking P2X7 but with improved antitumour capacity.

Nanomaterial‐Boosted Tumor Immunotherapy Through Natural Killer Cells

Natural killer (NK)‐cell immunotherapy as an alternative to T‐cell immunotherapy has been widely used in clinical cell immunotherapy of various tumors. Despite the surprising findings, the widespread applications of NK cells are still limited by the insufficient expansion and short lifespan of adoptive NK cells in vivo, the poor penetration of NK cells in solid tumors, as well as the immunosuppressive tumor microenvironment that may cause the inactivation of NK cells. Fortunately, the emergence of nanomaterials provides many opportunities to address these vexing problems, thus overcoming the barriers faced by NK cells and promoting the tumor inhibitory efficacy of NK cells. Herein, the recent advances in the rational design of nanomaterials for boosting the NK cell‐based immunotherapy, mainly through enhancing NK cell engagement with tumors, boosting NK cell activation or expansion, as well as redirecting NK cells to tumor cells, are reviewed. Lastly, the design and preparation of next‐generation nanomaterials that aim to further boost the NK cell‐based immunotherapy are briefly discussed.

Anticancer traits of chimeric antigen receptors (CARs)-Natural Killer (NK) cells as novel approaches for melanoma treatment

Owing to non-responsiveness of a high number of patients to the common melanoma therapies, seeking novel approaches seem as an unmet requirement. Chimeric antigen receptor (CAR) T cells were initially employed against recurrent or refractory B cell malignancies. However, advanced stages or pretreated patients have insufficient T cells (lymphopenia) amount for collection and clinical application. Additionally, this process is time-consuming and logistically cumbersome. Another limitation of this approach is toxicity and cytokine release syndrome (CRS) progress and neurotoxicity syndrome (NS). Natural killer (NK) cells are a versatile component of the innate immunity and have several advantages over T cells in the application for therapies such as availability, unique biological features, safety profile, cost effectiveness and higher tissue residence. Additionally, CAR NK cells do not develop Graft-versus-host disease (GvHD) and are independent of host HLA genotype. Notably, the NK cells number and activity is affected in the tumor microenvironment (TME), paving the way for developing novel approaches by enhancing their maturation and functionality. The CAR NK cells short lifespan is a double edge sword declining toxicity and reducing their persistence. Bispecific and Trispecific Killer Cell Engagers (BiKE and Trike, respectively) are emerging and promising immunotherapies for efficient antibody dependent cell cytotoxicity (ADCC). CAR NK cells have some limitations in terms of expanding and transducing NK cells from donors to achieve clinical response. Clinical trials are in scarcity regarding the CAR NK cell-based cancer therapies. The CAR NK cells short life span following irradiation before infusion limits their efficiency inhibiting their in vivo expansion. The CAR NK cells efficacy enhancement in terms of lifespan TME preparation and stability is a goal for melanoma treatment. Combination therapies using CAR NK cells and chemotherapy can also overcome therapy limitations.

Aurantii Fructus Immaturus enhances natural killer cytolytic activity and anticancer efficacy in vitro and in vivo

Aurantii Fructus Immaturus (AFI), extensively used in traditional herbal medicine, is known to have diverse physiological effects against various diseases, including obesity, diabetes, and cardiovascular disease. However, the effects of AFI on the immune system, especially natural killer (NK) cells, remain largely unknown. We aimed to investigate the effect of AFI on NK cell activity in vitro and in vivo and to elucidate the underlying mechanisms. Further, we verified the anticancer efficacy of AFI in a mouse lung metastasis model, underscoring the therapeutic potential of AFI in cancer therapy. Our results revealed that AFI significantly enhanced the cytolytic activity of NK cells in a dose-dependent manner, accompanied by an increase in the expression of NK cell-activating receptors, especially NKp30 and NKp46. AFI treatment also increased the expression of cytolytic granules, including granzyme B and perforin. Furthermore, the expression of CD107a, a degranulation marker, was increased upon treatment with AFI. A signaling study using western blot analysis demonstrated that the phosphorylation of extracellular signal-regulated kinase (ERK) was involved in increasing the NK cell activity following AFI treatment. In the in vivo study performed in mice, oral administration of AFI markedly enhanced the cytotoxic activity of spleen mononuclear cells against YAC-1 cells, which was accompanied by NKp46 upregulation. In addition, we confirmed that cancer metastasis was inhibited in a mouse cancer metastasis model, established using the mouse melanoma B16F10 cell line, by the administration of AFI in vivo. Collectively, these results indicate that AFI enhances NK cell-mediated cytotoxicity in vitro and in vivo via activation of the ERK signaling pathway and suggest that AFI could be a potential supplement for cancer immunotherapy.

HLA-G and CD152 Expression Levels Encourage the Use of Umbilical Cord Tissue-Derived Mesenchymal Stromal Cells as an Alternative for Immunosuppressive Therapy

Mesenchymal stromal cells (MSCs) have been used in immunosuppressive therapy due to their therapeutic effects, with the HLA-G molecule seeming to play a fundamental role. This work evaluated alternative MSC sources to bone marrow (BM), namely, umbilical cord tissue (UC), adipose tissue (AD) and dental pulp tissue (DP), and the influence of interferon-γ (IFN-γ) and hypoxia on the cultivation of these cells for use in immunosuppression therapies. Expression of costimulatory markers CD40, CD80 and CD86 and immunosuppressive molecules CD152 and HLA-G was analyzed. Lymphocyte inhibition assays were also performed. Sequencing of the HLA-G gene from exons 1 to 5 was performed using next-generation sequencing to determine the presence of alleles. UC-derived MSCs (UCMSCs) expressed higher CD152 and HLA-G1 under standard cultivation. UCMSCs and DP-derived MSCs (DPSCs) secreted similar levels of HLA-G5. All MSC sources inhibited the proliferation of peripheral blood mononuclear cells (PBMCs); growth under regular versus hypoxic conditions resulted in similar levels of inhibition. When IFN-γ was added, PBMC growth was inhibited to a lesser extent by UCMSCs. The HLA-G*01:04:01:01 allele appears to generate a more efficient MSC response in inhibiting lymphocyte proliferation. However, the strength of this conclusion was limited by the small sample size. UCMSCs are an excellent alternative to BM in immunosuppressive therapy: they express high concentrations of inhibitory molecules and can be cultivated without stimuli, which minimizes cost.

Mechanisms of immune activation and regulation: lessons from melanoma

Melanoma, a skin cancer that develops from pigment cells, has been studied intensively, particularly in terms of the immune response to tumours, and has been used as a model for the development of immunotherapy. This is due, in part, to the high mutational burden observed in melanomas, which increases both their immunogenicity and the infiltration of immune cells into the tumours, compared with other types of cancers. The immune response to melanomas involves a complex set of components and interactions. As the tumour evolves, it accumulates an increasing number of genetic and epigenetic alterations, some of which contribute to the immunogenicity of the tumour cells and the infiltration of immune cells. However, tumour evolution also enables the development of resistance mechanisms, which, in turn, lead to tumour immune escape. Understanding the interactions between melanoma tumour cells and the immune system, and the evolving changes within the melanoma tumour cells, the immune system and the microenvironment, is essential for the development of new cancer therapies. However, current research suggests that other extrinsic factors, such as the microbiome, may play a role in the immune response to melanomas. Here, we review the mechanisms underlying the immune response in the tumour and discuss recent advances as well as strategies for treatment development.

Combined Blockade of TIGIT and CD39 or A2AR Enhances NK-92 Cell-Mediated Cytotoxicity in AML

This study aimed to characterize different natural killer (NK) cell phenotypes on bone marrow and peripheral blood cells from acute myeloid leukemia (AML) patients and healthy donors (HDs). Our data show that CD56^dimCD16⁻ and CD56^brightCD16⁻ NK cells represent the predominant NK cell subpopulations in AML, while the CD56^dimCD16⁺ NK cells are significantly reduced compared to HDs. Moreover, TIGIT⁺ and PVRIG⁺ cells cluster on the CD56^dimCD16⁺ subset whereas CD39⁺ and CD38⁺ cells do so on CD56^brightCD16⁻ NK cells in AML. Furthermore, functional effects of (co-)blockade of TIGIT and CD39 or A2AR on NK cell functionality were analyzed. These experiments revealed that the single blockade of the TIGIT receptor results in an increased NK-92 cell-mediated killing of AML cells in vitro. Combined targeting of CD39 or A2AR significantly augments the anti-TIGIT-mediated lysis of AML cells. Our data indicate that distinct NK cell subsets in AML exhibit different immunosuppressive patterns (via the TIGIT/PVRIG receptors and the purinergic pathway). In summary, we conclude that TIGIT, CD39, and A2AR constitute relevant inhibitory checkpoints of NK cells in AML patients. A combinatorial blockade synergistically strengthens NK-92 cell-mediated cytotoxicity. As inhibitors of TIGIT, CD39, and A2AR are clinically available, studies on their combined use could be conducted in the near future.

Metformin promotes anticancer activity of NK cells in a p38 MAPK dependent manner

Metformin, a drug prescribed to treat type 2 diabetes, has been reported to possess antitumor activity via immunity activation. However, the influence of metformin on natural killer (NK) cells is not fully understood. Here, we investigated whether metformin exerts a potent anticancer effect by activating NK cells. The results showed that sustained exposure to metformin enhances the cytolytic activity of NK-92 cells. Moreover, this enhancement of cytotoxicity by metformin was also observed in NK cells from healthy peripheral blood and cancer patient ascites. Mechanistically, metformin induced activation of the JAK1/2/3/STAT5 and AKT/mTOR pathways in a p38 MAPK-dependent manner rather than an AMPK-dependent manner. In vivo experiments, metformin also improved cancer surveillance of NK cells in mouse models of lymphoma clearance and metastatic melanoma. Additionally, combination treatment with metformin and anti-PD-1 antibodies increased the therapy response rates of B16F10 melanoma. Moreover, metformin treatment increased NK cell and T cell infiltration in tumors. Therefore, these results provide a deeper understanding of metformin on the effector function of NK cells and will contribute to the development and applications of metformin in cancer treatment strategies.

NK Cells in the Tumor Microenvironment as New Potential Players Mediating Chemotherapy Effects in Metastatic Melanoma

Until the last decade, chemotherapy was the standard treatment for metastatic cutaneous melanoma, even with poor results. The introduction of immune checkpoints inhibitors (ICIs) radically changed the outcome, increasing 5-year survival from 5% to 60%. However, there is still a large portion of unresponsive patients that would need further therapies. NK cells are skin-resident innate cytotoxic lymphocytes that recognize and kill virus-infected as well as cancer cells thanks to a balance between inhibitory and activating signals delivered by surface molecules expressed by the target. Since NK cells are equipped with cytotoxic machinery but lack of antigen restriction and needing to be primed, they are nowadays gaining attention as an alternative to T cells to be exploited in immunotherapy. However, their usage suffers of the same limitations reported for T cells, that is the loss of immunogenicity by target cells and the difficulty to penetrate and be activated in the suppressive tumor microenvironment (TME). Several evidence showed that chemotherapy used in metastatic melanoma therapy possess immunomodulatory properties that may restore NK cells functions within TME. Here, we will discuss the capability of such chemotherapeutics to: i) up-regulate melanoma cells susceptibility to NK cell-mediated killing, ii) promote NK cells infiltration within TME, iii) target other immune cell subsets that affect NK cells activities. Alongside traditional systemic melanoma chemotherapy, a new pharmacological strategy based on nanocarriers loaded with chemotherapeutics is developing. The use of nanotechnologies represents a very promising approach to improve drug tolerability and effectiveness thanks to the targeted delivery of the therapeutic molecules. Here, we will also discuss the recent developments in using nanocarriers to deliver anti-cancer drugs within the melanoma microenvironment in order to improve chemotherapeutics effects. Overall, we highlight the possibility to use standard chemotherapeutics, possibly delivered by nanosystems, to enhance NK cells anti-tumor cytotoxicity. Combined with immunotherapies targeting NK cells, this may represent a valuable alternative approach to treat those patients that do not respond to current ICIs.

Crosstalk between Metabolic Disorders and Immune Cells

Metabolic syndrome results from multiple risk factors that arise from insulin resistance induced by abnormal fat deposition. Chronic inflammation owing to obesity primarily results from the recruitment of pro-inflammatory M1 macrophages into the adipose tissue stroma, as the adipocytes within become hypertrophied. During obesity-induced inflammation in adipose tissue, pro-inflammatory cytokines are produced by macrophages and recruit further pro-inflammatory immune cells into the adipose tissue to boost the immune response. Here, we provide an overview of the biology of macrophages in adipose tissue and the relationship between other immune cells, such as CD4+ T cells, natural killer cells, and innate lymphoid cells, and obesity and type 2 diabetes. Finally, we discuss the link between the human pathology and immune response and metabolism and further highlight potential therapeutic targets for the treatment of metabolic disorders.

EVI2B Is a New Prognostic Biomarker in Metastatic Melanoma with IFNgamma Associated Immune Infiltration

Simple Summary

Ecotropic viral integration site 2B (EVI2B) is a protein-coding gene known as a lymphocyte-specific marker in peripheral blood. However, the prognostic value of EVI2B expression in metastatic melanoma tissue and its detailed profile of tumor-infiltrating lymphocytes are still unclear. In publicly available datasets, we found that increased EVI2B was significantly associated with longer prognoses such as overall survival and disease-specific survival. The EVI2B-high melanoma tissue had a favorable distribution/clustering pattern of infiltrating lymphocytes with increased CD8+ T cells over regulatory T cells. Moreover, EVI2B expression correlated with multiple immunomodulatory genes including IFN-γ signature genes. In conclusion, EVI2B is a prognostic biomarker with IFN-γ associated immune infiltration in metastatic melanoma.

Abstract

Background: To assess the prognostic role and the antitumor immunological relevance of ecotropic viral integration site 2B (EVI2B) in metastatic melanoma. Methods: In this study, we integrated clinical data, mRNA expression data, and the distribution and fraction of tumor infiltrating lymphocytes (TILs) using The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) datasets (GSE65904 and GSE19234). Results: The univariate and multivariate analyses showed that higher gene expression of EVI2B was significantly associated with longer prognoses. The EVI2B-high melanoma tissue had favorable histological parameters such as a brisk global distribution pattern and clustering structure of TILs (i.e., Banfield and Raftery index) with enriched CD8+ T cells over regulatory T cells and increased cytotoxicity scores. In addition, EVI2B expression positively correlated with IFN-γ signature genes (CXCL10, CXCL9, HLA-DRA, IDO1, IFNG, and STAT1) and other various immunomodulatory genes. Conclusion: EVI2B is a novel prognostic biomarker with IFN-γ associated immune infiltration in metastatic melanoma.