Trial Watch: Immunostimulatory monoclonal antibodies in cancer therapy

Brown B, Chan TA, Chand D, Constanzo J, Demaria S, I. Gabrilovich D, Golden E, Godkin A, Guha C, P. Gupta G, Hasan A, G. Herrera F, Kaufman H, Li D, A. Melcher A, McDonald S, Merghoub T, Monjazeb AM, Paris S, Pitroda S, Sadanandam A, Schaue D, Santambrogio L, Szapary P, Sage J, W. Welsh J, Wilkins A, H. Young K, Wennerberg E, Zitvogel L, Galluzzi L, Deutsch E, C. Formenti S. Updates on radiotherapy-immunotherapy combinations: Proceedings of 8th Annual ImmunoRad Conference

The annual ImmunoRad Conference has established itself as a recurrent occasion to explore the possibility of combining radiation therapy (RT) and immunotherapy (IT) for clinical cancer management. Bringing together a number of preclinical and clinical leaders in the fields of radiation oncology, immuno-oncology and IT, this annual event fosters indeed essential conversations and fruitful exchanges on how to address existing challenges to expand the therapeutic value of RT-IT combinations. The 8th edition of the ImmunoRad Conference, which has been held in October 2024 at the Weill Cornell Medical College of New York City, highlighted exciting preclinical and clinical advances at the interface between RT and IT, setting the stage for extra progress toward extended benefits for patients with an increasing variety of tumor types. Here, we critically summarize the lines of investigation that have been discussed at the occasion of the 8th Annual ImmunoRad Conference.

Silicon-containing nanomedicine and biomaterials: materials chemistry, multi-dimensional design, and biomedical application

The invention of silica-based bioactive glass in the late 1960s has sparked significant interest in exploring a wide range of silicon-containing biomaterials from the macroscale to the nanoscale. Over the past few decades, these biomaterials have been extensively explored for their potential in diverse biomedical applications, considering their remarkable bioactivity, excellent biocompatibility, facile surface functionalization, controllable synthesis, etc. However, to expedite the clinical translation and the unexpected utilization of silicon-composed nanomedicine and biomaterials, it is highly desirable to achieve a thorough comprehension of their characteristics and biological effects from an overall perspective. In this review, we provide a comprehensive discussion on the state-of-the-art progress of silicon-composed biomaterials, including their classification, characteristics, fabrication methods, and versatile biomedical applications. Additionally, we highlight the multi-dimensional design of both pure and hybrid silicon-composed nanomedicine and biomaterials and their intrinsic biological effects and interactions with biological systems. Their extensive biomedical applications span from drug delivery and bioimaging to therapeutic interventions and regenerative medicine, showcasing the significance of their rational design and fabrication to meet specific requirements and optimize their theranostic performance. Additionally, we offer insights into the future prospects and potential challenges regarding silicon-composed nanomedicine and biomaterials. By shedding light on these exciting research advances, we aspire to foster further progress in the biomedical field and drive the development of innovative silicon-composed nanomedicine and biomaterials with transformative applications in biomedicine.

Multi-Institutional Evaluation of Pathologists' Assessment Compared to Immunoscore

BACKGROUND

The Immunoscore (IS) is a quantitative digital pathology assay that evaluates the immune response in cancer patients. This study reports on the reproducibility of pathologists' visual assessment of CD3+- and CD8+-stained colon tumors, compared to IS quantification.

METHODS

An international group of expert pathologists evaluated 540 images from 270 randomly selected colon cancer (CC) cases. Concordance between pathologists' T-score, corresponding hematoxylin-eosin (H&E) slides, and the digital IS was evaluated for two- and three-category IS.

RESULTS

Non-concordant T-scores were reported in more than 92% of cases. Disagreement between semi-quantitative visual assessment of T-score and the reference IS was observed in 91% and 96% of cases before and after training, respectively. Statistical analyses showed that the concordance index between pathologists and the digital IS was weak in two- and three-category IS, respectively. After training, 42% of cases had a change in T-score, but no improvement was observed with a Kappa of 0.465 and 0.374. For the 20% of patients around the cut points, no concordance was observed between pathologists and digital pathology analysis in both two- and three-category IS, before or after training (all Kappa < 0.12).

CONCLUSIONS

The standardized IS assay outperformed expert pathologists' T-score evaluation in the clinical setting. This study demonstrates that digital pathology, in particular digital IS, represents a novel generation of immune pathology tools for reproducible and quantitative assessment of tumor-infiltrated immune cell subtypes.

Frequencies of an Immunogenic HER-2/neu Epitope of CD8+ T Lymphocytes Predict Favorable Clinical Outcomes in Prostate Cancer

HER-2/neu is the human epidermal growth factor receptor 2, which is associated with the progression of prostate cancer (PCa). HER-2/neu-specific T cell immunity has been shown to predict immunologic and clinical responses in PCa patients treated with HER-2/neu peptide vaccines. However, its prognostic role in PCa patients receiving conventional treatment is unknown, and this was addressed in this study. The densities of CD8+ T cells specific for the HER-2/neu_(780-788) peptide in the peripheral blood of PCa patients under standard treatments were correlated with TGF-β/IL-8 levels and clinical outcomes. We demonstrated that PCa patients with high frequencies of HER-2/neu_(780-788)-specific CD8+ T lymphocytes had better progression-free survival (PFS) as compared with PCa patients with low frequencies. Increased frequencies of HER-2/neu_(780-788)-specific CD8+ T lymphocytes were also associated with lower levels of TGF-β and IL-8. Our data provide the first evidence of the predictive role of HER-2/neu-specific T cell immunity in PCa.

Autoantibodies - enemies, and/or potential allies?

Autoantibodies are well known as potentially highly harmful antibodies which attack the host via binding to self-antigens, thus causing severe associated diseases and symptoms (e.g. autoimmune diseases). However, detection of autoantibodies to a range of disease-associated antigens has enabled their successful usage as important tools in disease diagnosis, prognosis and treatment. There are several advantages of using such autoantibodies. These include the capacity to measure their presence very early in disease development, their stability, which is often much better than their related antigen, and the capacity to use an array of such autoantibodies for enhanced diagnostics and to better predict prognosis. They may also possess capacity for utilization in therapy, in vivo. In this review both the positive and negative aspects of autoantibodies are critically assessed, including their role in autoimmune diseases, cancers and the global pandemic caused by COVID-19. Important issues related to their detection are also highlighted.

Trial Watch: combination of tyrosine kinase inhibitors (TKIs) and immunotherapy

The past decades witnessed the clinical employment of targeted therapies including but not limited to tyrosine kinase inhibitors (TKIs) that restrain a broad variety of pro-tumorigenic signals. TKIs can be categorized into (i) agents that directly target cancer cells, (ii) normalize angiogenesis or (iii) affect cells of the hematologic lineage. However, a clear distinction of TKIs based on this definition is limited by the fact that many TKIs designed to inhibit cancer cells have also effects on immune cells that are being discovered. Additionally, TKIs originally designed to target hematological cancers exhibit bioactivities on healthy cells of the same hematological lineage. TKIs have been described to improve immune recognition and cancer immunosurveillance, providing the scientific basis to combine TKIs with immunotherapy. Indeed, combination of TKIs with immunotherapy showed synergistic effects in preclinical models and clinical trials and some combinations of TKIs normalizing angiogenesis with immune checkpoint blocking antibodies have already been approved by the FDA for cancer therapy. However, the identification of appropriate drug combinations as well as optimal dosing and scheduling needs to be improved in order to obtain tangible progress in cancer care. This Trial Watch summarizes active clinical trials combining TKIs with various immunotherapeutic strategies to treat cancer patients.

Local Destruction of Tumors and Systemic Immune Effects

Current immune-based therapies signify a major advancement in cancer therapy; yet, they are not effective in the majority of patients. Physically based local destruction techniques have been shown to induce immunologic effects and are increasingly used in order to improve the outcome of immunotherapies. The various local destruction methods have different modes of action and there is considerable variation between the different techniques with respect to the ability and frequency to create a systemic anti-tumor immunologic effect. Since the abscopal effect is considered to be the best indicator of a relevant immunologic effect, the present review focused on the tissue changes associated with this effect in order to find determinants for a strong immunologic response, both when local destruction is used alone and combined with immunotherapy. In addition to the T cell-inflammation that was induced by all methods, the analysis indicated that it was important for an optimal outcome that the released antigens were not destroyed, tumor cell death was necrotic and tumor tissue perfusion was at least partially preserved allowing for antigen presentation, immune cell trafficking and reduction of hypoxia. Local treatment with controlled low level hyperthermia met these requisites and was especially prone to result in abscopal immune activity on its own.

Nanoparticle-based approaches to target the lymphatic system for antitumor treatment

Immunotherapies have been established as safe and efficient modalities for numerous tumor treatments. The lymphatic system, which is an important system, can modulate the immune system via a complex network, which includes lymph nodes, vessels, and lymphocytes. With the deepening understanding of tumor immunology, a plethora of immunotherapies, which include vaccines, photothermal therapy, and photodynamic therapy, have been established for antitumor treatments. However, the deleterious off-target effects and nonspecific targeting of therapeutic agents result in low efficacy of immunotherapy. Fortunately, nanoparticle-based approaches for targeting the lymphatic system afford a unique opportunity to manufacture drugs that can simultaneously tackle both aspects, thereby improving tumor treatments. Over the past decades, great strides have been made in the development of DC vaccines and nanomedicine as antitumor treatments in the field of lymphatic therapeutics and diagnosis. In this review, we summarize the current strategies through which nanoparticle technology has been designed to target the lymphatic system and describe applications of lymphatic imaging for the diagnosis and image-guided surgery of tumor metastasis. Moreover, improvements in the tumor specificity of nanovaccines and medicines, which have been realized through targeting or stimulating the lymphatic system, can provide amplified antitumor immune responses and reduce side effects, thereby promoting the paradigm of antitumor treatment into the clinic to benefit patients.

Comprehensive analysis of macrophage-related multigene signature in the tumor microenvironment of head and neck squamous cancer

Macrophages are among the most abundant cells of the tumor microenvironment in head and neck squamous cancer (HNSC). Although the marker gene sets of macrophages have been found, the mechanism by which they affect macrophages and whether they further predict the clinical outcome is unclear. In this study, a univariate COX analysis and a random forest algorithm were used to construct a prognostic model. Differential expression of the key gene, methylation status, function, and signaling pathways were further analyzed. We cross-analyzed multiple databases to detect the relationship between the most critical gene and the infiltration of multiple immune cells, as well as its impact on the prognosis of pan-cancer. FANCE is recognized as hub gene by different algorithms. It was overexpressed in HNSC, and high expression was predictive of better prognosis. It might promote apoptosis through the Wnt/β-catenin pathway. The expression of FANCE is inversely proportional to the infiltration of CD4 + T cells and their subsets, tumor-associated macrophages (TAMs), M2 macrophages, but positively co-expressed with M1 macrophages. In summary, FANCE was identified as the hub gene from the macrophage marker gene set, and it may improve the prognosis of HNSC patients by inhibiting lymphocytes and tumor-associated macrophages infiltration.

The Role of Immunotherapy in the Treatment of Adrenocortical Carcinoma

Adrenocortical carcinoma (ACC) is a rare epithelial neoplasm, with a high tendency for local invasion and distant metastases, with limited treatment options. Surgical treatment is the method of choice. For decades, the mainstay of pharmacological treatment has been the adrenolytic drug mitotane, in combination with chemotherapy. Immunotherapy is the latest revolution in cancer therapy, however preliminary data with single immune checkpoint inhibitors showed a modest activity in ACC patients. The anti-neoplastic activity of immune checkpoint inhibitors such as anti-cytotoxic-T-lymphocyte-associated-antigen 4 (anti-CTLA-4), anti-programmed death-1 (anti-PD-1), and anti-PD-ligand-1 (PD-L1) antibodies in different solid tumors has aroused interest to explore the potential therapeutic effect in ACC as well. Multiple ongoing clinical trials are currently evaluating the role of immune checkpoint inhibitors in ACC (pembrolizumab, combination pembrolizumab and relacorilant, nivolumab, combination nivolumab and ipilimumab). The primary and acquired resistance to immunotherapy continue to counter treatment efficacy. Therefore, attempts are made to combine therapy: anti-PD-1 antibody and anti-CTLA-4 antibody, anti-PD-1 antibody and antagonist of the glucocorticoid receptor. The inhibitors of immune checkpoints would benefit patients with antitumor immunity activated by radiotherapy. Immunotherapy is well tolerated by patients; the most frequently observed side effects are mild. The most common adverse effects of immunotherapy are skin and gastrointestinal disorders. The most common endocrinopathy during anti-CTLA treatment is pituitary inflammation and thyroid disorders.

Chimeric antigen receptor-engineered natural killer cells for cancer immunotherapy

Natural killer (NK) cells are a critical component of the innate immune system. Chimeric antigen receptors (CARs) re-direct NK cells toward tumor cells carrying corresponding antigens, creating major opportunities in the fight against cancer. CAR NK cells have the potential for use as universal CAR cells without the need for human leukocyte antigen matching or prior exposure to tumor-associated antigens. Exciting data from recent clinical trials have renewed interest in the field of cancer immunotherapy due to the potential of CAR NK cells in the production of "off-the-shelf" anti-cancer immunotherapeutic products. Here, we provide an up-to-date comprehensive overview of the recent advancements in key areas of CAR NK cell research and identify under-investigated research areas. We summarize improvements in CAR design and structure, advantages and disadvantages of using CAR NK cells as an alternative to CAR T cell therapy, and list sources to obtain NK cells. In addition, we provide a list of tumor-associated antigens targeted by CAR NK cells and detail challenges in expanding and transducing NK cells for CAR production. We additionally discuss barriers to effective treatment and suggest solutions to improve CAR NK cell function, proliferation, persistence, therapeutic effectiveness, and safety in solid and liquid tumors.

Detection of immunogenic cell death and its relevance for cancer therapy

Chemotherapy, radiation therapy, as well as targeted anticancer agents can induce clinically relevant tumor-targeting immune responses, which critically rely on the antigenicity of malignant cells and their capacity to generate adjuvant signals. In particular, immunogenic cell death (ICD) is accompanied by the exposure and release of numerous damage-associated molecular patterns (DAMPs), which altogether confer a robust adjuvanticity to dying cancer cells, as they favor the recruitment and activation of antigen-presenting cells. ICD-associated DAMPs include surface-exposed calreticulin (CALR) as well as secreted ATP, annexin A1 (ANXA1), type I interferon, and high-mobility group box 1 (HMGB1). Additional hallmarks of ICD encompass the phosphorylation of eukaryotic translation initiation factor 2 subunit-α (EIF2S1, better known as eIF2α), the activation of autophagy, and a global arrest in transcription and translation. Here, we outline methodological approaches for measuring ICD markers in vitro and ex vivo for the discovery of next-generation antineoplastic agents, the development of personalized anticancer regimens, and the identification of optimal therapeutic combinations for the clinical management of cancer.

Trial watch: STING agonists in cancer therapy

Stimulator of interferon response cGAMP interactor 1 (STING1, best known as STING) is an endoplasmic reticulum-sessile protein that serves as a signaling hub, receiving input from several pattern recognition receptors, most of which sense ectopic DNA species in the cytosol. In particular, STING ensures the production of type I interferon (IFN) in response to invading DNA viruses, bacterial pathogens, as well as DNA leaking from mitochondria or the nucleus (e.g., in cells exposed to chemotherapy or radiotherapy). As a type I IFN is critical for the initiation of anticancer immune responses, the pharmaceutical industry has generated molecules that directly activate STING for use in oncological indications. Such STING agonists are being tested in clinical trials with the rationale of activating STING in tumor cells or tumor-infiltrating immune cells (including dendritic cells) to elicit immunostimulatory effects, alone or in combination with a range of established chemotherapeutic and immunotherapeutic regimens. In this Trial Watch, we discuss preclinical evidence and accumulating clinical experience shaping the design of Phase I and Phase II trials that evaluate the safety and preliminary efficacy of STING agonists in cancer patients.

Influence of antigen density and immunosuppressive factors on tumor-targeted costimulation with antibody-fusion proteins and bispecific antibody-mediated T cell response

Target expression heterogeneity and the presence of an immunosuppressive microenvironment can hamper severely the efficiency of immunotherapeutic approaches. We have analyzed the potential to encounter and overcome such conditions by a combinatory two-target approach involving a bispecific antibody retargeting T cells to tumor cells and tumor-directed antibody-fusion proteins with costimulatory members of the B7 and TNF superfamily. Targeting the tumor-associated antigens EpCAM and EGFR with the bispecific antibody and costimulatory fusion proteins, respectively, we analyzed the impact of target expression and the influence of the immunosuppressive factors IDO, IL-10, TGF-β, PD-1 and CTLA-4 on the targeting-mediated stimulation of T cells. Here, suboptimal activity of the bispecific antibody at diverse EpCAM expression levels could be effectively enhanced by targeting-mediated costimulation by B7.1, 4-1BBL and OX40L in a broad range of EGFR expression levels. Furthermore, the benefit of combined costimulation by B7.1/4-1BBL and 4-1BBL/OX40L was demonstrated. In addition, the expression of immunosuppressive factors was shown in all co-culture settings, where blocking of prominent factors led to synergistic effects with combined costimulation. Thus, targeting-mediated costimulation showed general promise for a broad application covering diverse target expression levels, with the option for further selective enhancement by the identification and blockade of main immunosuppressive factors of the particular tumor environment.

Trial watch: TLR3 agonists in cancer therapy

Toll-like receptor 3 (TLR3) is a pattern recognition receptor that senses exogenous (viral) as well as endogenous (mammalian) double-stranded RNA in endosomes. On activation, TLR3 initiates a signal transduction pathway that culminates with the secretion of pro-inflammatory cytokines including type I interferon (IFN). The latter is essential not only for innate immune responses to infection but also for the initiation of antigen-specific immunity against viruses and malignant cells. These aspects of TLR3 biology have supported the development of various agonists for use as stand-alone agents or combined with other therapeutic modalities in cancer patients. Here, we review recent preclinical and clinical advances in the development of TLR3 agonists for oncological disorders.

Abbreviations

cDC, conventional dendritic cell; CMT, cytokine modulating treatment; CRC, colorectal carcinoma; CTL, cytotoxic T lymphocyte; DC, dendritic cell; dsRNA, double-stranded RNA; FLT3LG, fms-related receptor tyrosine kinase 3 ligand; HNSCC, head and neck squamous cell carcinoma; IFN, interferon; IL, interleukin; ISV, in situ vaccine; MUC1, mucin 1, cell surface associated; PD-1, programmed cell death 1; PD-L1, programmed death-ligand 1; polyA:U, polyadenylic:polyuridylic acid; polyI:C, polyriboinosinic:polyribocytidylic acid; TLR, Toll-like receptor.

Engineering nanoparticles to reprogram radiotherapy and immunotherapy: recent advances and future challenges

Nanoparticles (NPs) have been increasingly studied for radiosensitization. The principle of NPs radio-enhancement is to use high-atomic number NPs (e.g. gold, hafnium, bismuth and gadolinium) or deliver radiosensitizing substances, such as cisplatin and selenium. Nowadays, cancer immunotherapy is emerged as a promising treatment and immune checkpoint regulation has a potential property to improve clinical outcomes in cancer immunotherapy. Furthermore, NPs have been served as an ideal platform for immunomodulator system delivery. Owing to enhanced permeability and retention (EPR) effect, modified-NPs increase the targeting and retention of antibodies in target cells. The purpose of this review is to highlight the latest progress of nanotechnology in radiotherapy (RT) and immunotherapy, as well as combining these three strategies in cancer treatment. Overall, nanomedicine as an effective strategy for RT can significantly enhance the outcome of immunotherapy response and might be beneficial for clinical transformation.

Nanoparticle Delivery of Immunostimulatory Agents for Cancer Immunotherapy

Immunostimulatory agents, including adjuvants, cytokines, and monoclonal antibodies, hold great potential for the treatment of cancer. However, their direct administration often results in suboptimal pharmacokinetics, vulnerability to biodegradation, and compromised targeting. More recently, encapsulation into biocompatible nanoparticulate carriers has become an emerging strategy for improving the delivery of these immunotherapeutic agents. Such approaches can address many of the challenges facing current treatment modalities by endowing additional protection and significantly elevating the bioavailability of the encapsulated payloads. To further improve the delivery efficiency and subsequent immune responses associated with current nanoscale approaches, biomimetic modifications and materials have been employed to create delivery platforms with enhanced functionalities. By leveraging nature-inspired design principles, these biomimetic nanodelivery vehicles have the potential to alter the current clinical landscape of cancer immunotherapy.

Multi-antigen Vaccination With Simultaneous Engagement of the OX40 Receptor Delays Malignant Mesothelioma Growth and Increases Survival in Animal Models

Malignant Mesothelioma (MM) is a rare and highly aggressive cancer that develops from mesothelial cells lining the pleura and other internal cavities, and is often associated with asbestos exposure. To date, no effective treatments have been made available for this pathology. Herein, we propose a novel immunotherapeutic approach based on a unique vaccine targeting a series of antigens that we found expressed in different MM tumors, but largely undetectable in normal tissues. This vaccine, that we term p-Tvax, is comprised of a series of immunogenic peptides presented by both MHC-I and -II to generate robust immune responses. The peptides were designed using in silico algorithms that discriminate between highly immunogenic T cell epitopes and other harmful epitopes, such as suppressive regulatory T cell epitopes and autoimmune epitopes. Vaccination of mice with p-Tvax led to antigen-specific immune responses that involved both CD8⁺ and CD4⁺ T cells, which exhibited cytolytic activity against MM cells in vitro. In mice carrying MM tumors, p-Tvax increased tumor infiltration of CD4⁺ T cells. Moreover, combining p-Tvax with an OX40 agonist led to decreased tumor growth and increased survival. Mice treated with this combination immunotherapy displayed higher numbers of tumor-infiltrating CD8⁺ and CD4⁺ T cells and reduced T regulatory cells in tumors. Collectively, these data suggest that the combination of p-Tvax with an OX40 agonist could be an effective strategy for MM treatment.

Future of cancer immunotherapy using plant virus-based nanoparticles

Immunotherapy potentiates a patient’s immune response against some forms of cancer, including malignant tumors. In this Special Report, we have summarized the use of nanoparticles that have been designed for use in cancer immunotherapy with particular emphasis on plant viruses. Plant virus-based nanoparticles are an ideal choice for therapeutic applications, as these nanoparticles are not only capable of targeting the desired cells but also of being safely delivered to the body without posing any threat of infection. Plant viruses can be taken up by tumor cells and can be functionalized as drug delivery vehicles. This Special Report describes how the future of cancer immunotherapy could be a success through the merger of computer-based technology using plant-virus nanoparticles.

The nonpathogenic nature of plant viral nanoparticles makes them an ideal choice for therapeutic applications such as cancer. Understanding the molecular mechanisms behind the immune response to cancer has facilitated the use of nanotechnology as an effective cancer therapy. Biologically active self-replicating plant virus particles can be introduced to the bloodstream of the human body and used as effective drug delivery vehicles. This Special Report describes how a combination of computer-based technology and plant-virus nanoparticles can assist in cancer immunotherapy.

Trial watch: dendritic cell vaccination for cancer immunotherapy

Dendritic- cells (DCs) have received considerable attention as potential targets for the development of anticancer vaccines. DC-based anticancer vaccination relies on patient-derived DCs pulsed with a source of tumor-associated antigens (TAAs) in the context of standardized maturation-cocktails, followed by their reinfusion. Extensive evidence has confirmed that DC-based vaccines can generate TAA-specific, cytotoxic T cells. Nonetheless, clinical efficacy of DC-based vaccines remains suboptimal, reflecting the widespread immunosuppression within tumors. Thus, clinical interest is being refocused on DC-based vaccines as combinatorial partners for T cell-targeting immunotherapies. Here, we summarize the most recent preclinical/clinical development of anticancer DC vaccination and discuss future perspectives for DC-based vaccines in immuno-oncology.

Trial watch: dietary interventions for cancer therapy

Dietary interventions have a profound impact on whole body metabolism, including oncometabolism (the metabolic features allowing cancer cells to proliferate) and immunometabolism (the catabolic and anabolic reactions that regulate immune responses). Recent preclinical studies demonstrated that multiple dietary changes can improve anticancer immunosurveillance of chemo-, radio- and immunotherapy. These findings have fostered the design of clinical trials evaluating the capacity of dietary interventions to synergize with treatment and hence limit tumor progression. Here, we discuss the scientific rationale for harnessing dietary interventions to improve the efficacy of anticancer therapy and present up-to-date information on clinical trials currently investigating this possibility.

Advances in immunotherapy delivery from implantable and injectable biomaterials

Macroscale biomaterials, such as preformed implantable scaffolds and injectable soft materials, possess powerful synergies with anti-cancer immunotherapies. Immunotherapies on their own typically have poor delivery properties, and often require repeated high-dose injections that result in serious off-tumor effects and/or limited efficacy. Rationally designed biomaterials allow for discrete localization and controlled release of immunotherapeutic agents, and have been shown in a large number of applications to improve outcomes in the treatment of cancers via immunotherapy. Among various strategies, macroscale biomaterial delivery systems can take the form of robust tablet-like scaffolds that are surgically implanted into a tumor resection site, releasing programmed immune cells or immunoregulatory agents. Alternatively they can be developed as soft gel-like materials that are injected into solid tumors or sites of resection to stimulate a potent anti-tumor immune response. Biomaterials synthesized from diverse components such as polymers and peptides can be combined with any immunotherapy in the modern toolbox, from checkpoint inhibitors and stimulatory adjuvants, to cancer antigens and adoptive T cells, resulting in unique synergies and improved therapeutic efficacy. The field is growing rapidly in size as publications continue to appear in the literature, and biomaterial-based immunotherapies are entering clinical trials and human patients. It is unarguably an exciting time for cancer immunotherapy and biomaterial researchers, and further work seeks to understand the most critical design considerations in the development of the next-generation of immunotherapeutic biomaterials. This review will discuss recent advances in the delivery of immunotherapies from localized biomaterials, focusing on macroscale implantable and injectable systems. STATEMENT OF SIGNIFICANCE: Anti-cancer immunotherapies have shown exciting clinical results in the past few decades, yet they suffer from a few distinct limitations, such as poor delivery kinetics, narrow patient response profiles, and systemic side effects. Biomaterial systems are now being developed that can overcome many of these problems, allowing for localized adjuvant delivery, focused dose concentrations, and extended therapy presentation. The field of biocompatible carrier materials is uniquely suited to be combined with immunotherapy, promising to yield significant improvements in treatment outcomes and clinical care. In this review, the first pioneering efforts and most recent advances in biomaterials for immunotherapeutic applications are explored, with a specific focus on implantable and injectable biomaterials such as porous scaffolds, cryogels, and hydrogels.

Direct RIG-I activation in human NK cells induces TRAIL-dependent cytotoxicity toward autologous melanoma cells

Activation of the innate immune receptor retinoic acid-inducible gene I (RIG-I) by its specific ligand 5'-triphosphate RNA (3pRNA) triggers anti-tumor immunity, which is dependent on natural killer (NK) cell activation and cytokine induction. However, to date, RIG-I expression and the functional consequences of RIG-I activation in NK cells have not been examined. Here, we show for the first time the expression of RIG-I in human NK cells and their activation upon RIG-I ligand (3pRNA) transfection. 3pRNA-activated NK cells killed melanoma cells more efficiently than NK cells activated by type I interferon. Stimulation of RIG-I in NK cells specifically increased the surface expression of membrane-bound TNF-related apoptosis-inducing ligand (TRAIL) on NK cells, while activated NK cell receptors were not affected. RIG-I-induced membrane-bound TRAIL initiated death-receptor-pathway-mediated apoptosis not only in allogeneic but also in autologous human leukocyte antigen (HLA) class I-positive and HLA class I-negative melanoma cells. These results identify the direct activation of RIG-I in NK cells as a novel mechanism for how RIG-I can trigger enhanced NK cell killing of tumor cells, underscoring the potential of RIG-I activation for tumor immunotherapy.

Cold Tumors: A Therapeutic Challenge for Immunotherapy

Therapeutic monoclonal antibodies targeting immune checkpoints (ICPs) have changed the treatment landscape of many tumors. However, response rate remains relatively low in most cases. A major factor involved in initial resistance to ICP inhibitors is the lack or paucity of tumor T cell infiltration, characterizing the so-called “cold tumors.” In this review, we describe the main mechanisms involved in the absence of T cell infiltration, including lack of tumor antigens, defect in antigen presentation, absence of T cell activation and deficit of homing into the tumor bed. We discuss then the different therapeutic approaches that could turn cold into hot tumors. In this way, specific therapies are proposed according to their mechanism of action. In addition, ‘‘supra-physiological’’ therapies, such as T cell recruiting bispecific antibodies and Chimeric Antigen Receptor (CAR) T cells, may be active regardless of the mechanism involved, especially in MHC class I negative tumors. The determination of the main factors implicated in the lack of preexisting tumor T cell infiltration is crucial for the development of adapted algorithms of treatments for cold tumors.

Trial watch: Peptide-based vaccines in anticancer therapy

Peptide-based anticancer vaccination aims at stimulating an immune response against one or multiple tumor-associated antigens (TAAs) following immunization with purified, recombinant or synthetically engineered epitopes. Despite high expectations, the peptide-based vaccines that have been explored in the clinic so far had limited therapeutic activity, largely due to cancer cell-intrinsic alterations that minimize antigenicity and/or changes in the tumor microenvironment that foster immunosuppression. Several strategies have been developed to overcome such limitations, including the use of immunostimulatory adjuvants, the co-treatment with cytotoxic anticancer therapies that enable the coordinated release of damage-associated molecular patterns, and the concomitant blockade of immune checkpoints. Personalized peptide-based vaccines are also being explored for therapeutic activity in the clinic. Here, we review recent preclinical and clinical progress in the use of peptide-based vaccines as anticancer therapeutics.Abbreviations: CMP: carbohydrate-mimetic peptide; CMV: cytomegalovirus; DC: dendritic cell; FDA: Food and Drug Administration; HPV: human papillomavirus; MDS: myelodysplastic syndrome; MHP: melanoma helper vaccine; NSCLC: non-small cell lung carcinoma; ODD: orphan drug designation; PPV: personalized peptide vaccination; SLP: synthetic long peptide; TAA: tumor-associated antigen; TNA: tumor neoantigen

Trial Watch: Oncolytic viro-immunotherapy of hematologic and solid tumors

Oncolytic viruses selectively target and kill cancer cells in an immunogenic fashion, thus supporting the establishment of therapeutically relevant tumor-specific immune responses. In 2015, the US Food and Drug Administration (FDA) approved the oncolytic herpes simplex virus T-VEC for use in advanced melanoma patients. Since then, a plethora of trials has been initiated to assess the safety and efficacy of multiple oncolytic viruses in patients affected with various malignancies. Here, we summarize recent preclinical and clinical progress in the field of oncolytic virotherapy.

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.

Immune checkpoint molecules in acute myeloid leukaemia: managing the double-edged sword

New immunotherapeutic interventions have revolutionized cancer treatment. The immune responsiveness of acute myeloid leukaemia (AML) was first demonstrated by allogeneic stem cell transplantation. In addition, milder immunotherapeutic approaches are exploited. However, the long-term efficacy of these therapies is hampered by various immune resistance and editing mechanisms. In this regard, co-inhibitory signalling pathways have been shown to play a crucial role. Via up-regulation of inhibitory checkpoints, tumour-reactive T cell and Natural Killer cell responses can be strongly impeded. Accordingly, the introduction of checkpoint inhibitors targeting CTLA-4 (CTLA4) and PD-1 (PDCD1, CD279)/PD-L1 (CD274, PDCD1LG1) accomplished a breakthrough in cancer treatment, with impressive clinical responses. Numerous new co-inhibitory players and novel combination therapies are currently investigated for their potential to boost anti-tumour immunity and improve survival of cancer patients. Although the challenge here remains to avoid severe systemic toxicity. This review addresses the involvement of co-inhibitory signalling in AML immune evasion and discusses the opportunities for checkpoint blockers in AML treatment.

Advances in T-cell checkpoint immunotherapy for head and neck squamous cell carcinoma

Head and neck squamous cell carcinoma (HNSCC) has been found to be a complex group of malignancies characterized by their profound immunosuppression and high aggressiveness. In most cases of advanced HNSCC, treatment fails to obtain total cancer cure. Efforts are needed to develop new therapeutic approaches to improve HNSCC outcomes. In this light, T-cells "immune checkpoint" has attracted much attention in cancer immunotherapy. It has been broadly accepted that inhibitory T-cell immune checkpoints contribute to tumor immune escape through negative immune regulatory signals (cytotoxic T-lymphocyte-associated antigen 4 [CTLA-4], programmed cell death 1 [PD-1], B7-H3, and B7-H4, etc). Current data suggest that PD-1 and CTLA-4 receptors can inhibit T-cell receptors and T-cell proliferation. Blockade of PD-1/PD-L1 and/or CTLA-4/CD28 pathways has shown promising tumor outcomes in clinical trials for advanced solid tumors like melanoma, renal cell cancer, and non-small cell lung cancer. The present review attempts to explore what is known about PD-1/PD-L1 and CTLA-4/CD28 pathways with a focus on HNSCC. We further discuss how these pathways can be manipulated with therapeutic intent.

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.

Tumor-targeted costimulation with antibody-fusion proteins improves bispecific antibody-mediated immune response in presence of immunosuppressive factors

Therapeutic strategies aiming for the induction of an effective immune response at the tumor site can be severely hampered by the encounter of an immunosuppressive microenvironment. We investigated here the potential of concerted costimulation by tumor-directed antibody-fusion proteins with B7.1, 4-1BBL and OX40L to enforce bispecific antibody-induced T cell stimulation in presence of recognized immunosuppressive factors including IL-10, TGF-β, indoleamine 2,3-dioxygenase (IDO), PD-L1 and regulatory T cells. The expression and activity of these factors was demonstrated in the HT1080-FAP/PBMC co-culture setting, where individual and combined costimulation were still capable to enhance T cell stimulation, even though the general activation level was reduced. Additional blockade of TGF-ß or PD-1 resulted especially effective in further enhancing the degree of T cell activation. Here, best outcome was achieved by combined costimulation of targeted 4-1BBL and B7.1. Furthermore, their individual impact on the proliferation of naïve, memory and effector CD8⁺ and CD4⁺ T cell subsets, suggest the coverage of a comprehensive T cell response. Thus, our costimulatory antibody-fusion proteins show great potential to support T cell activation in adverse conditions dictated by the tumor microenvironment.

Isobavachalcone inhibits the proliferation and invasion of tongue squamous cell carcinoma cells

Isobavachalcone (2′,4′,4-trihydroxy-3′-[3′-methylbut-3′-ethyl] chalcone or IBC) exhibits anticancer activities in a number of types of cancer cell. However, its role in tongue squamous cell carcinoma (TSCC) cells remains unclear. The aim of the present study was to investigate the biological effect of IBC in TSCC Tca8113 cells. The function of IBC on Tca8113 cell apoptosis and apoptosis-associated signaling pathways was determined using an MTT assay, morphological staining, annexin V-propidium iodide (PI) staining and Western blot analysis. The effects of IBC on Tca8113 cell migration, invasion and relative protein expression were confirmed using wound healing analysis, Transwell invasion analysis and Western blot analysis, respectively. The results of the MTT assay and annexin V-PI staining indicated that IBC is able to significantly inhibit proliferation and induce apoptosis of Tca8113 cells in vitro. IBC treatment resulted in typical apoptotic morphology of nuclear fragmentation and apoptotic bodies in Tca8113 cells. Western blot analysis further demonstrated that IBC caused downregulation of the expression of B-cell lymphoma 2 (Bcl-2) protein, upregulation of the expression of Bcl-2-associated X protein (Bax), activation of caspases, and dephosphorylation of protein kinase B (Akt) and extracellular-signal-regulated kinase (ERK) proteins in a concentration- and time-dependent manner. The results of the present study suggest that IBC induces apoptosis in Tca8113 cells and that the induction may be associated with the activation of Bcl-2, Bax and caspase-3, and the inactivation of Akt and ERK. Furthermore, IBC inhibited migration and invasion of Tca8113 cells in vitro by downregulating matrix metalloproteinase (MMP)-2 and MMP-9 protein expression. The results of the present study indicate that IBC may be a potential anticancer drug for the treatment of TSCC.

Advances in the Immunobiological Therapies for Advanced Melanoma

Metastatic or locally advanced unresectable melanoma carries a high morbidity and mortality. However, notable advances have been made in recent years in the systemic treatment of this disease, with the appearance of targeted therapy using tyrosine kinase inhibitors that block the mitogen activated protein kinase pathway, and of modern immunotherapy with immune-modulating monoclonal antibodies. In this paper, we provide an update of available data on new immune therapies and we review the clinical development that led to their approval for use in routine clinical practice.

Second- and third-generation drugs for immuno-oncology treatment-The more the better?

Recent success in cancer immunotherapy (anti-CTLA-4, anti-PD1/PD-L1) has confirmed the hypothesis that the immune system can control many cancers across various histologies, in some cases producing durable responses in a way not seen with many small-molecule drugs. However, only less than 25% of all patients do respond to immuno-oncology drugs and several resistance mechanisms have been identified (e.g. T-cell exhaustion, overexpression of caspase-8 and β-catenin, PD-1/PD-L1 gene amplification, MHC-I/II mutations). To improve response rates and to overcome resistance, novel second- and third-generation immuno-oncology drugs are currently evaluated in ongoing phase I/II trials (either alone or in combination) including novel inhibitory compounds (e.g. TIM-3, VISTA, LAG-3, IDO, KIR) and newly developed co-stimulatory antibodies (e.g. CD40, GITR, OX40, CD137, ICOS). It is important to note that co-stimulatory agents strikingly differ in their proposed mechanism of action compared with monoclonal antibodies that accomplish immune activation by blocking negative checkpoint molecules such as CTLA-4 or PD-1/PD-1 or others. Indeed, the prospect of combining agonistic with antagonistic agents is enticing and represents a real immunologic opportunity to 'step on the gas' while 'cutting the brakes', although this strategy as a novel cancer therapy has not been universally endorsed so far. Concerns include the prospect of triggering cytokine-release syndromes, autoimmune reactions and hyper immune stimulation leading to activation-induced cell death or tolerance, however, toxicity has not been a major issue in the clinical trials reported so far. Although initial phase I/II clinical trials of agonistic and novel antagonistic drugs have shown highly promising results in the absence of disabling toxicity, both in single-agent studies and in combination with chemotherapy or other immune system targeting drugs; however, numerous questions remain about dose, schedule, route of administration and formulation as well as identifying the appropriate patient populations. In our view, with such a wealth of potential mechanisms of action and with the ability to fine-tune monoclonal antibody structure and function to suit particular requirements, the second and third wave of immuno-oncology drugs are likely to provide rapid advances with new combinations of novel immunotherapy (especially co-stimulatory antibodies). Here, we will review the mechanisms of action and the clinical data of these new antibodies and discuss the major issues facing this rapidly evolving field.

Experimental animal modeling for immuno-oncology

Immuno-oncology (I/O) research has intensified significantly in recent years due to the breakthrough development and the regulatory approval of several immune checkpoint inhibitors, leading to the rapid expansion of the new discovery of novel I/O therapies, new checkpoint inhibitors and beyond. However, many I/O questions remain unanswered, including why only certain subsets of patients respond to these treatments, who the responders would be, and how to expand patient response (the conversion of non-responders or maximizing response in partial responders). All of these require relevant I/O experimental systems, particularly relevant preclinical animal models. Compared to other oncology drug discovery, e.g. cytotoxic and targeted drugs, a lack of relevant animal models is a major obstacle in I/O drug discovery, and an urgent and unmet need. Despite the obvious importance, and the fact that much I/O research has been performed using many different animal models, there are few comprehensive and introductory reviews on this topic. This article attempts to review the efforts in development of a variety of such models, as well as their applications and limitations for readers new to the field, particularly those in the pharmaceutical industry.

Advancing targeted co-stimulation with antibody-fusion proteins by introducing TNF superfamily members in a single-chain format

Co-stimulation via receptors of the tumor necrosis factor superfamily (TNFSF) emerges as promising strategy to support antitumor immune responses. Targeted strategies with antibody-fusion proteins composed of a tumor-directed antibody part and the extracellular domain of a co-stimulatory ligand of the TNFSF constitute an attractive option to focus the co-stimulatory activity to the tumor site. Since TNFSF members intrinsically form functional units of non-covalently linked homotrimers, the protein engineering of suitable antibody-fusion proteins is challenging. Aiming for molecules of simple and stable configuration, we used TNFSF ligands in a single-chain format (scTNFSF), i.e., three units of the ectodomain connected by polypeptide linkers, folding into an intramolecular trimer. By fusing tumor-directed scFv antibody fragments directed against EpCAM or FAP to co-stimulatory scTNFSF molecules (sc4-1BBL, scOX40L, scGITRL or scLIGHT), a set of monomeric scFv-scTNFSF fusion proteins was generated. In comparison to the scFv-TNFSF format, defined by intermolecular homotrimerization via the TNFSF part, scFv-scTNFSF showed equal or enhanced co-stimulatory activity despite reduced avidity in antibody binding. In addition, enhanced serum stability and improved bioavailability in mice were observed. We show that the scFv-scTNFSF format can be applied to various members of the TNFSF, presenting targeting-dependent co-stimulatory activity. Hence, this format exhibits favorable properties that make it a promising choice for further therapeutic fusion protein development.

Endogenous T-Cell Therapy: Clinical Experience

Adoptive cellular therapy represents a robust means of augmenting the tumor-reactive effector population in patients with cancer by adoptive transfer of ex vivo expanded T cells. Three approaches have been developed to achieve this goal: the use of tumor-infiltrating lymphocytes or tumor-infiltrating lymphocytess extracted from patient biopsy material; the redirected engineering of lymphocytes using vectors expressing a chimeric antigen receptor and T-cell receptor; and third, the isolation and expansion of often low-frequency endogenous T cells (ETCs) reactive to tumor antigens from the peripheral blood of patients. This last form of adoptive transfer of T cells, known as ETC therapy, requires specialized methods to isolate and expand from peripheral blood the very low-frequency tumor-reactive T cells, methods that have been developed over the last 2 decades, to the point where such an approach may be broadly applicable not only for the treatment of melanoma but also for that of other solid tumor malignancies. One compelling feature of ETC is the ability to rapidly deploy clinical trials following identification of a tumor-associated target epitope, a feature that may be exploited to develop personalized antigen-specific T-cell therapy for patients with almost any solid tumor. With a well-validated antigen discovery pipeline in place, clinical studies combining ETC with agents that modulate the immune microenvironment can be developed that will transform ETC into a feasible treatment modality.

Trial Watch: Immunotherapy plus radiation therapy for oncological indications

Malignant cells succumbing to some forms of radiation therapy are particularly immunogenic and hence can initiate a therapeutically relevant adaptive immune response. This reflects the intrinsic antigenicity of malignant cells (which often synthesize a high number of potentially reactive neo-antigens) coupled with the ability of radiation therapy to boost the adjuvanticity of cell death as it stimulates the release of endogenous adjuvants from dying cells. Thus, radiation therapy has been intensively investigated for its capacity to improve the therapeutic profile of several anticancer immunotherapies, including (but not limited to) checkpoint blockers, anticancer vaccines, oncolytic viruses, Toll-like receptor (TLR) agonists, cytokines, and several small molecules with immunostimulatory effects. Here, we summarize recent preclinical and clinical advances in this field of investigation.

Trial Watch-Small molecules targeting the immunological tumor microenvironment for cancer therapy

Progressing malignancies establish robust immunosuppressive networks that operate both systemically and locally. In particular, as tumors escape immunosurveillance, they recruit increasing amounts of myeloid and lymphoid cells that exert pronounced immunosuppressive effects. These cells not only prevent the natural recognition of growing neoplasms by the immune system, but also inhibit anticancer immune responses elicited by chemo-, radio- and immuno therapeutic interventions. Throughout the past decade, multiple strategies have been devised to counteract the accumulation or activation of tumor-infiltrating immunosuppressive cells for therapeutic purposes. Here, we review recent preclinical and clinical advances on the use of small molecules that target the immunological tumor microenvironment for cancer therapy. These agents include inhibitors of indoleamine 2,3-dioxigenase 1 (IDO1), prostaglandin E2, and specific cytokine receptors, as well as modulators of intratumoral purinergic signaling and arginine metabolism.

Non-Small-Cell Lung Cancer: Role of the Immune System and Potential for Immunotherapy

As the leading cause of cancer death worldwide, lung cancer continues to impose a major burden on healthcare systems and cause significant challenges for clinicians and patients. Most patients present with advanced disease at the time of diagnosis and have a poor prognosis, with the vast majority surviving less than 5 years. Although new therapies have been introduced in recent years that target molecular disease drivers present in a subset of patients, there is a significant need for treatments able to improve response and extend survival while minimizing effects on quality of life. Recent evidence of clinical efficacy for immunotherapeutic approaches for lung cancer suggests that they will become the next major therapeutic advance for this disease. Non-small-cell lung cancer, which accounts for approximately 85% of lung cancer cases, has historically been considered a nonimmunogenic disease; however, as with several other malignancies, recent data show that much of this lack of immune responsiveness is functional rather than structural (i.e., possible to overcome therapeutically). This review explores the key elements of the immune system involved in non-small-cell lung cancer and briefly examines immunotherapeutic strategies in development to shift the balance of immune activity away from a tumor-induced immune-suppressive state toward an active antitumor immune response.

Antiviral Monoclonal Antibodies: Can They Be More Than Simple Neutralizing Agents?

Monoclonal antibodies (mAbs) are increasingly being considered as agents to fight severe viral diseases. So far, they have essentially been selected and used on the basis of their virus-neutralizing activity and/or cell-killing activity to blunt viral propagation via direct mechanisms. There is, however, accumulating evidence that they can also induce long-lasting protective antiviral immunity by recruiting the endogenous immune system of infected individuals during the period of immunotherapy. Exploiting this property may revolutionize antiviral mAb-based immunotherapies, with benefits for both patients and healthcare systems.

Antiviral monoclonal antibodies (mAbs) are promising, high-added-value biotherapeutics. During recent years, the number of antiviral mAbs developed against both acute and chronic viruses has grown exponentially, some of them being currently tested in clinical trials.

Antiviral mAbs can be used to blunt viral propagation through direct effects. They can also engage the host's immune system, leading to the induction of long-lasting protective vaccine-like effects.

The assessment of mechanisms at play in the induction of vaccine-like effects by antiviral mAbs will help in improving antiviral treatments.

Exploiting this effect will translate into therapeutic benefit for patients. The benefit will also help healthcare systems through the reduction of treatment costs.

CD137 and CD137L signals are main drivers of type 1, cell-mediated immune responses

CD137 is expressed on activated T cells and NK cells, among others, and is a potent co-stimulator of antitumor immune responses. CD137 ligand (CD137L) is expressed by antigen presenting cells (APC), and CD137L reverse signaling into APC enhances their activity. CD137-CD137L interactions as main driver of type 1, cell-mediated immune responses explains the puzzling observation that CD137 agonists which enhance antitumor immune responses also ameliorate autoimmune diseases. Upon co-stimulation by CD137, Th1 CD4+ T cells together with Tc1 CD8+ T cells and NK cells inhibit other T cell subsets, thereby promoting antitumor responses and mitigating non-type 1 auto-immune diseases.

Trial Watch-Oncolytic viruses and cancer therapy

Oncolytic virotherapy relies on the administration of non-pathogenic viral strains that selectively infect and kill malignant cells while favoring the elicitation of a therapeutically relevant tumor-targeting immune response. During the past few years, great efforts have been dedicated to the development of oncolytic viruses with improved specificity and potency. Such an intense wave of investigation has culminated this year in the regulatory approval by the US Food and Drug Administration (FDA) of a genetically engineered oncolytic viral strain for use in melanoma patients. Here, we summarize recent preclinical and clinical advances in oncolytic virotherapy.

Polyfunctional Melan-A-specific tumor-reactive CD8(+) T cells elicited by dacarbazine treatment before peptide-vaccination depends on AKT activation sustained by ICOS

The identification of activation pathways linked to antitumor T-cell polyfunctionality in long surviving patients is of great relevance in the new era of immunotherapy. We have recently reported that dacarbazine (DTIC) injected one day before peptide-vaccination plus IFN-α improves the antitumor lytic activity and enlarges the repertoire of Melan-A-specific T-cell clones, as compared with vaccination alone, impacting the overall survival of melanoma patients. To identify the mechanisms responsible for this improvement of the immune response, we have analyzed the endogenous and treatment-induced antigen (Ag)-specific response in a panel of Melan-A-specific CD8⁺ T-cell clones in terms of differentiation phenotype, inhibitory receptor profile, polyfunctionality and AKT activation. Here, we show that Melan-A-specific CD8⁺ T cells isolated from patients treated with chemoimmunotherapy possess a late differentiated phenotype as defined by the absence of CD28 and CD27 co-stimulatory molecules and high levels of LAG-3, TIM-3 and PD-1 inhibitory receptors. Nevertheless, they show higher proliferative potential and an improved antitumor polyfunctional effector profile in terms of co-production of TNF-α, IFNγ and Granzyme-B (GrB) compared with cells derived from patients treated with vaccination alone. Polyfunctionality is dependent on an active AKT signaling related to the engagement of the co-stimulatory molecule ICOS. We suggest that this phenotypic and functional signature is dictated by a fine-tuned balance between TCR triggering, AKT activation, co-stimulatory and inhibitory signals induced by chemoimmunotherapy and may be associated with antitumor T cells able to protect patients from tumor recurrence.

STAT3 inhibition for cancer therapy: Cell-autonomous effects only?

A paper recently published in Science Translational Medicine describes a next-generation antisense oligonucleotide that specifically downregulates the expression of human signal transducer and activator of transcription 3 (STAT3). Such an oligonucleotide, AZD9150, exerts antineoplastic effects on a selected panel of STAT3-dependent human cancer cells growing in vitro and in vivo (as xenografts in immunodeficient mice). Moreover, preliminary data from a Phase I clinical trial indicate that AZD9150 may cause partial tumor regression in patients with chemorefractory lymphoma and non-small cell lung carcinoma. STAT3 not only participates in cell-autonomous processes that are required for the survival and growth of malignant cells, but also limits their ability to elicit anticancer immune responses. Moreover, STAT3 contribute to the establishment of an immunosuppressive tumor microenvironment. Thus, the inhibition of STAT3 may promote immunosurveillance by a dual mechanism: (1) it may increase the immunogenicity of cancer cells via cell-autonomous pathways; and (2) it may favor the reprogramming of the tumor microenvironment toward an immunostimulatory state. It will therefore be important to explore whether immunological biomarkers predict the efficacy of AZD9150 in the clinic. This may ameliorate patient stratification and it may pave the way for rational combination therapies involving classical chemotherapeutics with immunostimulatory effects, AZD9150 and immunotherapeutic agents such as checkpoint blockers.

Immune Checkpoint Modulators: An Emerging Antiglioma Armamentarium

Immune checkpoints have come to the forefront of cancer therapies as a powerful and promising strategy to stimulate antitumor T cell activity. Results from recent preclinical and clinical studies demonstrate how checkpoint inhibition can be utilized to prevent tumor immune evasion and both local and systemic immune suppression. This review encompasses the key immune checkpoints that have been found to play a role in tumorigenesis and, more specifically, gliomagenesis. The review will provide an overview of the existing preclinical and clinical data, antitumor efficacy, and clinical applications for each checkpoint with respect to GBM, as well as a summary of combination therapies with chemotherapy and radiation.