IFNγ-Dependent Tissue-Immune Homeostasis Is Co-opted in the Tumor Microenvironment

Unleashing Type-2 Dendritic Cells to Drive Protective Antitumor CD4+ T Cell Immunity

Differentiation of proinflammatory CD4⁺ conventional T cells (T_conv) is critical for productive antitumor responses yet their elicitation remains poorly understood. We comprehensively characterized myeloid cells in tumor draining lymph nodes (tdLN) of mice and identified two subsets of conventional type-2 dendritic cells (cDC2) that traffic from tumor to tdLN and present tumor-derived antigens to CD4⁺ T_conv, but then fail to support antitumor CD4⁺ T_conv differentiation. Regulatory T cell (T_reg) depletion enhanced their capacity to elicit strong CD4⁺ T_conv responses and ensuing antitumor protection. Analogous cDC2 populations were identified in patients, and as in mice, their abundance relative to T_reg predicts protective ICOS⁺ PD-1^lo CD4⁺ T_conv phenotypes and survival. Further, in melanoma patients with low T_reg abundance, intratumoral cDC2 density alone correlates with abundant CD4⁺ T_conv and with responsiveness to anti-PD-1 therapy. Together, this highlights a pathway that restrains cDC2 and whose reversal enhances CD4⁺ T_conv abundance and controls tumor growth.

Interferon-induced guanylate-binding proteins: Guardians of host defense in health and disease

Guanylate-binding proteins (GBPs) have recently emerged as central orchestrators of immunity to infection, inflammation, and neoplastic diseases. Within numerous host cell types, these IFN-induced GTPases assemble into large nanomachines that execute distinct host defense activities against a wide variety of microbial pathogens. In addition, GBPs customize inflammasome responses to bacterial infection and sepsis, where they act as critical rheostats to amplify innate immunity and regulate tissue damage. Similar functions are becoming evident for metabolic inflammatory syndromes and cancer, further underscoring the importance of GBPs within infectious as well as altered homeostatic settings. A better understanding of the basic biology of these IFN-induced GTPases could thus benefit clinical approaches to a wide spectrum of important human diseases.

Why Innate Lymphoid Cells?

Innate lymphoid cells (ILCs) are positioned in tissues perinatally, constitutively express receptors responsive to their organ microenvironments, and perform an arsenal of effector functions that overlap those of adaptive CD4⁺ T cells. Based on knowledge regarding subsets of invariant-like lymphocytes (e.g., natural killer T [NKT] cells, γδ T cells, mucosal-associated invariant T [MAIT] cells, etc.) and fetally derived macrophages, we hypothesize that immune cells established during the perinatal period-including, but not limited to, ILCs-serve intimate roles in tissue that go beyond classical understanding of the immune system in microbial host defense. In this Perspective, we propose mechanisms by which the establishment of ILCs and the tissue lymphoid niche during early development may have consequences much later in life. Although definitive answers require better tools, efforts to achieve deeper understanding of ILC biology across the mammalian lifespan have the potential to lift the veil on the unknown breadth of immune cell functions.

Interferon-γ Receptor Signaling in Dendritic Cells Restrains Spontaneous Proliferation of CD4+ T Cells in Chronic Lymphopenic Mice

In lymphopenic mice, T cells become activated and undergo lymphopenia-induced proliferation (LIP). However, not all T cells are equally sensitive to lymphopenia. Several lymphopenia-insensitive T cell clones were described and their non-responsiveness was mainly attributed to clone-specific properties. Here, we provide evidence for an additional, host-dependent mechanism restraining LIP of lymphopenia-insensitive CD4+ T cells. We show that such cells undergo LIP in lymphopenic mice lacking IFN-γ receptor (IFN-γR) expression, a process, which is promoted by the autocrine action of T cell-derived IFN-γ. Additionally, LIP of lymphopenia-insensitive CD4+ T cells requires an intact microflora and is accompanied by the massive accumulation of IL-6 and dendritic cells (DCs). Consistent with these results, IL-6 neutralization and the DC-specific restoration of IFN-γR expression are both sufficient to restrict LIP. Hence, the insensitivity of CD4+ T cells to lymphopenia relies on cell-intrinsic properties and a complex interplay between the commensal microflora, IL-6, IFN-γR+ DCs, and T cell-derived IFN-γ.

Low-dose anti-inflammatory combinatorial therapy reduced cancer stem cell formation in patient-derived preclinical models for tumour relapse prevention

Background

Emergence of drug-resistant cancer phenotypes is a challenge for anti-cancer therapy. Cancer stem cells are identified as one of the ways by which chemoresistance develops.

Method

We investigated the anti-inflammatory combinatorial treatment (DA) of doxorubicin and aspirin using a preclinical microfluidic model on cancer cell lines and patient-derived circulating tumour cell clusters. The model had been previously demonstrated to predict patient overall prognosis.

Results

We demonstrated that low-dose aspirin with a sub-optimal dose of doxorubicin for 72 h could generate higher killing efficacy and enhanced apoptosis. Seven days of DA treatment significantly reduced the proportion of cancer stem cells and colony-forming ability. DA treatment delayed the inhibition of interleukin-6 secretion, which is mediated by both COX-dependent and independent pathways. The response of patients varied due to clinical heterogeneity, with 62.5% and 64.7% of samples demonstrating higher killing efficacy or reduction in cancer stem cell (CSC) proportions after DA treatment, respectively. These results highlight the importance of using patient-derived models for drug discovery.

Conclusions

This preclinical proof of concept seeks to reduce the onset of CSCs generated post treatment by stressful stimuli. Our study will promote a better understanding of anti-inflammatory treatments for cancer and reduce the risk of relapse in patients.

Revolutionizing Cancer Immunology: The Power of Next-Generation Sequencing Technologies

It has long been appreciated that tumors are diverse, varying in mutational status, composition of cellular infiltrate, and organizational architecture. For the most part, the information embedded in this diversity has gone untapped due to the limited resolution and dimensionality of assays for analyzing nucleic acid expression in cells. The advent of high-throughput, next-generation sequencing (NGS) technologies that measure nucleic acids, particularly at the single-cell level, is fueling the characterization of the many components that comprise the tumor microenvironment (TME), with a strong focus on immune composition. Understanding the immune and nonimmune components of the TME, how they interact, and how this shapes their functional properties requires the development of novel computational methods and, eventually, the application of systems-based approaches. The continued development and application of NGS technologies holds great promise for accelerating discovery in the cancer immunology field.

Novel immune signatures associated with dysplastic naevi and primary cutaneous melanoma in human skin

Dysplastic naevi (DN) are benign lesions with atypical features intermediate between that of common melanocytic naevi (CMN) and malignant melanoma (MM). Debate remains over whether DN represent progressive lesions from CMN. Through gene expression profiling and analysis of molecular gene signatures, our study revealed progressive increases in immune activation and regulation, along with pathways implicated in melanomagenesis, from CMN to DN to MM. Using criteria of 1.5-fold change and false discovery rate ≤0.05, we found differential expression of 7186 probes (6370 unique genes) with the largest difference detected between DN and MM from the standpoint of genomic melanoma progression. Despite progressive increases in the T-helper type 1 (Th1)-inducing gene (IL-12), RT-PCR indicated impaired Th1 or cytotoxic T-cell response (decreased IFN-γ) in MM. Concordantly, our results indicated progressive increases in molecular markers associated with regulatory T cells, exhausted T cells and tolerogenic dendritic cells, including detection of increased expression of suppressor of cytokine signalling 3 (SOCS3) in dendritic cells associated with MM. All together, our findings suggest that the increased immunosuppressive microenvironment of melanoma may contribute to unhampered proliferation of neoplastic cells. In addition, the detection of increased markers associated with tolerogenic dendritic cells in MM suggests that targeting these suppressive immune cell types may represent an alternative avenue for future immunotherapy.

Successful Anti-PD-1 Cancer Immunotherapy Requires T Cell-Dendritic Cell Crosstalk Involving the Cytokines IFN-γ and IL-12

Anti-PD-1 immune checkpoint blockers can induce sustained clinical responses in cancer but how they function in vivo remains incompletely understood. Here, we combined intravital real-time imaging with single-cell RNA sequencing analysis and mouse models to uncover anti-PD-1 pharmacodynamics directly within tumors. We showed that effective antitumor responses required a subset of tumor-infiltrating dendritic cells (DCs), which produced interleukin 12 (IL-12). These DCs did not bind anti-PD-1 but produced IL-12 upon sensing interferon γ (IFN-γ) that was released from neighboring T cells. In turn, DC-derived IL-12 stimulated antitumor T cell immunity. These findings suggest that full-fledged activation of antitumor T cells by anti-PD-1 is not direct, but rather involves T cell:DC crosstalk and is licensed by IFN-γ and IL-12. Furthermore, we found that activating the non-canonical NF-κB transcription factor pathway amplified IL-12-producing DCs and sensitized tumors to anti-PD-1 treatment, suggesting a therapeutic strategy to improve responses to checkpoint blockade.

Human bone marrow assessment by single-cell RNA sequencing, mass cytometry, and flow cytometry

New techniques for single-cell analysis have led to insights into hematopoiesis and the immune system, but the ability of these techniques to cross-validate and reproducibly identify the biological variation in diverse human samples is currently unproven. We therefore performed a comprehensive assessment of human bone marrow cells using both single-cell RNA sequencing and multiparameter flow cytometry from 20 healthy adult human donors across a broad age range. These data characterize variation between healthy donors as well as age-associated changes in cell population frequencies. Direct comparison of techniques revealed discrepancy in the quantification of T lymphocyte and natural killer cell populations. Orthogonal validation of immunophenotyping using mass cytometry demonstrated a strong correlation with flow cytometry. Technical replicates using single-cell RNA sequencing matched robustly, while biological replicates showed variation. Given the increasing use of single-cell technologies in translational research, this resource serves as an important reference data set and highlights opportunities for further refinement.

IFNγ-activated dermal lymphatic vessels inhibit cytotoxic T cells in melanoma and inflamed skin

Mechanisms of immune suppression in peripheral tissues counteract protective immunity to prevent immunopathology and are coopted by tumors for immune evasion. While lymphatic vessels facilitate T cell priming, they also exert immune suppressive effects in lymph nodes at steady-state. Therefore, we hypothesized that peripheral lymphatic vessels acquire suppressive mechanisms to limit local effector CD8+ T cell accumulation in murine skin. We demonstrate that nonhematopoietic PD-L1 is largely expressed by lymphatic and blood endothelial cells and limits CD8+ T cell accumulation in tumor microenvironments. IFNγ produced by tissue-infiltrating, antigen-specific CD8+ T cells, which are in close proximity to tumor-associated lymphatic vessels, is sufficient to induce lymphatic vessel PD-L1 expression. Disruption of IFNγ-dependent crosstalk through lymphatic-specific loss of IFNγR boosts T cell accumulation in infected and malignant skin leading to increased viral pathology and tumor control, respectively. Consequently, we identify IFNγR as an immunological switch in lymphatic vessels that balances protective immunity and immunopathology leading to adaptive immune resistance in melanoma.

Tumour heterogeneity and metastasis at single-cell resolution

Tumours comprise a heterogeneous collection of cells with distinct genetic and phenotypic properties that can differentially promote progression, metastasis and drug resistance. Emerging single-cell technologies provide a new opportunity to profile individual cells within tumours and investigate what roles they play in these processes. This Review discusses key technological considerations for single-cell studies in cancer, new findings using single-cell technologies and critical open questions for future applications.

The Interferon-Gamma Paradox in Cancer

Interferon-gamma (IFNG) has long been implicated as a central orchestrator of antitumor immune responses in the elimination stage of the immunoediting paradigm. However, mounting evidence suggests that IFNG may also have important and significant protumor roles to play in the equilibrium and escape phases through its regulatory effects on immunoevasive functions that promote tumorigenesis. These seemingly contradictory effects of IFNG undoubtedly play profound roles in not only the activation of inflammatory response to cancer but also in the determination of its outcome. In the face of the recent explosion of anticancer immunotherapeutic strategies in the clinic, it is critical that a complete understanding is achieved of the underpinnings of the mechanisms that determine the two faces of IFNG signaling in cancer. Here, the current state of this dichotomy is reviewed.

Critical role of post-transcriptional regulation for IFN-γ in tumor-infiltrating T cells

Protective T cell responses against tumors require the production of Interferon gamma (IFN-γ). However, tumor-infiltrating T cells (TILs) gradually lose their capacity to produce IFN-γ and therefore fail to clear malignant cells. Dissecting the underlying mechanisms that block cytokine production is thus key for improving T cell products. Here we show that although TILs express substantial levels of Ifng mRNA, post-transcriptional mechanisms impede the production of IFN-γ protein due to loss of mRNA stability. CD28 triggering, but not PD1 blocking antibodies, effectively restores the stability of Ifng mRNA. Intriguingly, TILs devoid of AU-rich elements within the 3'untranslated region maintain stabilized Ifng mRNA and produce more IFN-γ protein than wild-type TILs. This sustained IFN-γ production translates into effective suppression of tumor outgrowth, which is almost exclusively mediated by direct effects on the tumor cells. We therefore conclude that post-transcriptional mechanisms could be modulated to potentiate effective T cell therapies in cancer.

Integrating the skin and blood transcriptomes and serum proteome in hidradenitis suppurativa reveals complement dysregulation and a plasma cell signature

Hidradenitis suppurativa (HS) is a chronic skin disease of the pilo-sebaceous apocrine unit characterized by significant inflammation and an impaired quality of life. The pathogenesis of HS remains unclear. To determine the HS skin and blood transcriptomes and HS blood proteome, patient data from previously published studies were analysed and integrated from a cohort of patients with moderate to severe HS (n = 17) compared to healthy volunteers (n = 10). The analysis utilized empirical Bayes methods to determine differentially expressed genes (DEGs) (fold change (FCH) >2.0 and false discovery rate (FDR) <0.05), and differentially expressed proteins (DEPs) (FCH>1.5, FDR<0.05). In the HS skin transcriptome (lesional skin compared to non-lesional skin), there was an abundance of immunoglobulins, antimicrobial peptides, and an interferon signature. Gene-sets related to Notch signalling and Interferon pathways were differentially activated in lesional compared to non-lesional skin. CIBERSORT analysis of the HS skin transcriptome revealed a significantly increased proportion of plasma cells in lesional skin. In the HS skin and blood transcriptomes and HS blood proteome, gene-sets related to the complement system changed significantly (FDR<0.05), with dysregulation of complement-specific DEGs and DEPs. These data point towards an exaggerated immune response in lesional skin that may be responding to commensal cutaneous bacterial presence and raise the possibility that this may be an important driver of HS disease progression.

New advances in immunotherapy for non-small cell lung cancer

Immunotherapy is one of the methods that can change the survival rate of patients with malignant tumors, in addition to surgery therapy, radiotherapy, chemotherapy and targeted therapy. Among various immunotherapy methods, immunoprecipitation inhibitors have been the most effective medications developed in recent years. At present, more in-depth studies have been conducted for two immune checkpoint inhibitor pathways, programmed cell death protein 1 (PD-1)/Programmed death-ligand 1 (PD-L1) and cytotoxic T-lymphocyte-associated antigen-4 (CTLA-4), and a variety of medications for those above mentioned. The present study briefly reviews the results of clinical trials for relevant immune checkpoint inhibitors in lung cancer.

Interferon gamma in cancer immunotherapy

Immune system can recognize self vs transformed self. That is why cancer immunotherapy achieves notable benefits in a wide variety of cancers. Recently, several papers reported that immune checkpoint blockade therapy led to upregulation of IFNγ and in turn clearance of tumor cells. In this review, we conducted an extensive literature search of recent 5‐year studies about the roles of IFNγ signaling in both tumor immune surveillance and immune evasion. In addition to well‐known functions, IFNγ signaling also induces tumor ischemia and homeostasis program, resulting in tumor clearance and tumor escape, respectively. The yin and the yang of IFNγ signaling are summarized. Thus, this review helps us to comprehensively understand the roles of IFNγ in tumor immunity, which contributes to better design and management of clinical immunotherapy approaches.

The impact of single-cell RNA sequencing on understanding the functional organization of the immune system

Application of single-cell genomics technologies has revolutionized our approach to study the immune system. Unravelling the functional diversity of immune cells and their coordinated response is key to understanding immunity. Single-cell transcriptomics technologies provide high-dimensional assessment of the transcriptional states of immune cells and have been successfully applied to discover new immune cell types, reveal haematopoietic lineages, identify gene modules dictating immune responses and investigate lymphocyte antigen receptor diversity. In this review, we discuss the impact and applications of single-cell RNA sequencing technologies in immunology.

PPARγ Contributes to Immunity Induced by Cancer Cell Vaccines That Secrete GM-CSF

Peroxisome proliferator activated receptor-γ (PPARγ) is a lipid-activated nuclear receptor that promotes immune tolerance through effects on macrophages, dendritic cells (DCs), and regulatory T cells (Tregs). Granulocyte-macrophage colony stimulating factor (GM-CSF) induces PPARγ expression in multiple myeloid cell types. GM-CSF contributes to both immune tolerance and protection, but the role of PPARγ in these pathways is poorly understood. Here, we reveal an unexpected stimulatory role for PPARγ in the generation of antitumor immunity with irradiated, GM-CSF-secreting tumor-cell vaccines (GVAX). Mice harboring a deletion of pparg in lysozyme M (LysM)-expressing myeloid cells (KO) showed a decreased ratio of CD8⁺ T effectors to Tregs and impaired tumor rejection with GVAX. Diminished tumor protection was associated with altered DC responses and increased production of the Treg attracting chemokines CCL17 and CLL22. Correspondingly, the systemic administration of PPARγ agonists to vaccinated mice elevated the CD8⁺ T effector to Treg ratio through effects on myeloid cells and intensified the antitumor activity of GVAX combined with cytotoxic T lymphocyte-associated antigen-4 antibody blockade. PPARγ agonists similarly attenuated Treg induction and decreased CCL17 and CCL22 levels in cultures of human peripheral blood mononuclear cells with GM-CSF-secreting tumor cells. Together, these results highlight a key role for myeloid cell PPARγ in GM-CSF-stimulated antitumor immunity and suggest that PPARγ agonists might be useful in cancer immunotherapy. Cancer Immunol Res; 6(6); 723-32. ©2018 AACR.

SOCS-mediated immunomodulation of natural killer cells

Natural killer (NK) cells are innate immune cells with an intrinsic ability to detect and kill infected and cancerous cells. The success of therapies targeting immune checkpoints on CD8 cells has intensified interest in harnessing the cytolytic effector functions of NK cells for new cancer treatments. NK cell development, survival and effector activity is dependent on exposure to the cytokine interleukin (IL)-15. The suppressor of cytokine (SOCS) proteins (CIS; SOCS1-7) are important negative regulators of cytokine signaling, and both CIS and SOCS2 are reported to have roles in regulating NK cell responses. Their immunomodulatory effects on NK cells suggest that these SOCS proteins are promising targets that can potentially form the basis of novel cancer therapies. Here we discuss the role of NK cells in tumor immunity as well as review the role of the SOCS proteins in regulating IL-15 signaling and NK cell function.

Strategies on Nanodiagnostics and Nanotherapies of the Three Common Cancers

The emergence of nanomedicine has enriched the knowledge and strategies of treating diseases, and especially some incurable diseases, such as cancers, acquired immune deficiency syndrome (AIDS), and neurodegenerative diseases. The application of nanoparticles in medicine is in the core of nanomedicine. Nanoparticles can be used in drug delivery for improving the uptake of poorly soluble drugs, targeted delivery to a specific site, and drug bioavailability. Early diagnosis of and targeted therapies for cancers can significantly improve patients' quality of life and extend patients' lives. The advantages of nanoparticles have given them a progressively important role in the nanodiagnosis and nanotherapy of common cancers. To provide a reference for the further application of nanoparticles, this review focuses on the recent development and application of nanoparticles in the early diagnosis and treatment of the three common cancers (lung cancer, liver cancer, and breast cancer) by using quantum dots, magnetic nanoparticles, and gold nanoparticles.

Trial Watch: Immunostimulation with recombinant cytokines for cancer therapy

Cytokines regulate virtually aspects of innate and adaptive immunity, including the initiation, execution and extinction of tumor-targeting immune responses. Over the past three decades, the possibility of using recombinant cytokines as a means to elicit or boost clinically relevant anticancer immune responses has attracted considerable attention. However, only three cytokines have been approved so far by the US Food and Drug Administration and the European Medicines Agency for use in cancer patients, namely, recombinant interleukin (IL)-2 and two variants of recombinant interferon alpha 2 (IFN-α2a and IFN-α2b). Moreover, the use of these cytokines in the clinics is steadily decreasing, mostly as a consequence of: (1) the elevated pleiotropism of IL-2, IFN-α2a and IFN-α2b, resulting in multiple unwarranted effects; and (2) the development of highly effective immunostimulatory therapeutics, such as immune checkpoint blockers. Despite this and other obstacles, research in the field continues as alternative cytokines with restricted effects on specific cell populations are being evaluated. Here, we summarize research preclinical and clinical developments on the use of recombinant cytokines for immunostimulation in cancer patients.

Prolonged skin grafts survival time by IFN-γ in allogeneic skin transplantation model during acute rejection through IFN-γ/STAT3/IDO pathway in epidermal layer

Allogeneic skin transplantation is the life-saving therapy for multiple diseases, including extensive burn, large-scale trauma and certain post-surgical complications. However, acute rejection impedes clinical application of allogeneic skin transplantation. Although a lot of novel immunosuppressant drugs have been developed, there is still great need for ideal therapy with less complication and more therapeutic effects. Here, we found interferon gamma (IFN-γ) as an immunomodulatory cytokine prolonged the survival time of allografts from (8.50 ± 1.517) days to (14.83 ± 2.714) days at best. Indoleamine-2, 3-dioxygenase (IDO) has been proposed to play key roles in induction of immune tolerance. Using in vitro tissue culture and primary keratinocytes and fibroblasts, we investigated the regulatory effects of IFN-γ on the IDO expression. IFN-γ upregulated IDO expression through STAT3 phosphorylation and this upregulation was reduced by abolition of STAT3 phosphorylation through a STAT3 phosphorylation inhibitor. Interestingly, IFN-γ induced IDO expression predominately in epidermis rather than dermis. In consistent with these results, IFN-γ significantly triggered IDO expression in keratinocytes but not fibroblasts. Taken together, this suggests that IFN-γ might be a potential immunomodulatory drug in acute rejection and keratinocytes in epidermis may play a main role in immune tolerance after allogeneic skin transplantation.

The Dark Side of IFN-γ: Its Role in Promoting Cancer Immunoevasion

Interferon-γ (IFN-γ) is a pleiotropic cytokine that has long been praised as an important effector molecule of anti-tumor immunity, capable of suppressing tumor growth through various mechanisms. On the contrary to such a bright side of IFN-γ, it has also been involved in promoting an outgrowth of tumor cells with immunoevasive phenotype suggesting an existence of a dark "tumor-promoting" side effect of IFN-γ. In this review, we will summarize this multi-functional role of IFN-γ in tumor context, how it promotes changes in tumor phenotype towards increased fitness for growth in immunocompetent host. Furthermore, we summarize how IFN-γ is involved in homeostatic or cancer-triggered mechanisms to establish an immunosuppressive tumor microenvironment.

Natural Killer Cells Control Tumor Growth by Sensing a Growth Factor

Many tumors produce platelet-derived growth factor (PDGF)-DD, which promotes cellular proliferation, epithelial-mesenchymal transition, stromal reaction, and angiogenesis through autocrine and paracrine PDGFRβ signaling. By screening a secretome library, we found that the human immunoreceptor NKp44, encoded by NCR2 and expressed on natural killer (NK) cells and innate lymphoid cells, recognizes PDGF-DD. PDGF-DD engagement of NKp44 triggered NK cell secretion of interferon gamma (IFN)-γ and tumor necrosis factor alpha (TNF-α) that induced tumor cell growth arrest. A distinctive transcriptional signature of PDGF-DD-induced cytokines and the downregulation of tumor cell-cycle genes correlated with NCR2 expression and greater survival in glioblastoma. NKp44 expression in mouse NK cells controlled the dissemination of tumors expressing PDGF-DD more effectively than control mice, an effect enhanced by blockade of the inhibitory receptor CD96 or CpG-oligonucleotide treatment. Thus, while cancer cell production of PDGF-DD supports tumor growth and stromal reaction, it concomitantly activates innate immune responses to tumor expansion.

Natural killer cells and anti-tumor immunity

Immune checkpoint inhibitors harness the power of the immune system to fight cancer. The clinical success achieved with antibodies against the inhibitory T cell receptors PD-1 and CTLA4 has focused attention on the possibility of manipulating other immune cells, in particular those involved in innate immunity. Here we review the role of innate lymphoid cells (ILCs) and their contribution to tumor immunity. As the prototypical ILC, the natural killer (NK) cell has an intrinsic ability to detect and kill cancer cells. NK cells are dependent on the cytokine interleukin (IL)-15 for their development and effector activity. We discuss the role of the Suppressor of cytokine (SOCS) proteins in negatively regulating IL-15 and NK cell responses and the potential for targeting these small intracellular regulators as new immune checkpoints.

Trial watch: Immunogenic cell death induction by anticancer chemotherapeutics

The expression "immunogenic cell death" (ICD) refers to a functionally unique form of cell death that facilitates (instead of suppressing) a T cell-dependent immune response specific for dead cell-derived antigens. ICD critically relies on the activation of adaptive responses in dying cells, culminating with the exposure or secretion of immunostimulatory molecules commonly referred to as "damage-associated molecular patterns". Only a few agents can elicit bona fide ICD, including some clinically established chemotherapeutics such as doxorubicin, epirubicin, idarubicin, mitoxantrone, bleomycin, bortezomib, cyclophosphamide and oxaliplatin. In this Trial Watch, we discuss recent progress on the development of ICD-inducing chemotherapeutic regimens, focusing on studies that evaluate clinical efficacy in conjunction with immunological biomarkers.

Ontogeny and function of murine epidermal Langerhans cells

Langerhans cells (LCs) are epidermis-resident antigen-presenting cells that share a common ontogeny with macrophages but function as dendritic cells (DCs). Their development, recruitment and retention in the epidermis is orchestrated by interactions with keratinocytes through multiple mechanisms. LC and dermal DC subsets often show functional redundancy, but LCs are required for specific types of adaptive immune responses when antigen is concentrated in the epidermis. This Review will focus on those developmental and functional properties that are unique to LCs.

Trial watch: Immune checkpoint blockers for cancer therapy

Immune checkpoint blockers (ICBs) are literally revolutionizing the clinical management of an ever more diversified panel of oncological indications. Although considerable attention persists around the inhibition of cytotoxic T lymphocyte-associated protein 4 (CTLA4) and programmed cell death 1 (PDCD1, best known as PD-1) signaling, several other co-inhibitory T-cell receptors are being evaluated as potential targets for the development of novel ICBs. Moreover, substantial efforts are being devoted to the identification of biomarkers that reliably predict the likelihood of each patient to obtain clinical benefits from ICBs in the absence of severe toxicity. Tailoring the delivery of specific ICBs or combinations thereof to selected patient populations in the context of precision medicine programs constitutes indeed a major objective of the future of ICB-based immunotherapy. Here, we discuss recent preclinical and clinical advances on the development of ICBs for oncological indications.

Trial Watch: Immunostimulatory monoclonal antibodies for oncological indications

The goal of cancer immunotherapy is to establish new or boost pre-existing anticancer immune responses that eradicate malignant cells while generating immunological memory to prevent disease relapse. Over the past few years, immunomodulatory monoclonal antibodies (mAbs) that block co-inhibitory receptors on immune effectors cells - such as cytotoxic T lymphocyte-associated protein 4 (CTLA4), programmed cell death 1 (PDCD1, best known as PD-1) - or their ligands - such as CD274 (best known as PD-L1) - have proven very successful in this sense. As a consequence, many of such immune checkpoint blockers (ICBs) have already entered the clinical practice for various oncological indications. Considerable attention is currently being attracted by a second group of immunomodulatory mAbs, which are conceived to activate co-stimulatory receptors on immune effector cells. Here, we discuss the mechanisms of action of these immunostimulatory mAbs and summarize recent progress in their preclinical and clinical development.

Interferon with antitumor immunity

IFN-γ directs homeostatic differentiation of tissue APCs but may subvert aspects of tumor immune surveillance.