Cancer Immunotherapy: Beyond Checkpoint Blockade

CD8+ T cells in breast cancer tumors and draining lymph nodes: PD-1 levels, effector functions and prognostic relevance

CD8+ T cells shape the antitumor immune response. Here, we evaluated CD8+ T cells expressing different levels of PD-1, their functional status, and distribution in different tissues of luminal breast cancer (BC) patients. We characterized the exhaustion stages of CD8+ T cells in tumors, juxtatumoral tissues (JTs), and tumor-draining lymph nodes (TDLNs). Terminal exhausted CD8+ T cells (PD-1High CD8+) were predominant in tumors and nearly absent in other tissues. However, in all tissues evaluated, most CD8+ T cells exhibited a pre-exhausted phenotype (PD-1Int CD8+) or did not express PD-1. PD-1High and PD-1Int CD8+ T cells from tumors and JTs presented central and effector memory phenotypes, while in TDLNs were primarily central memory. TCR-β sequencing revealed higher clonality among CD8+ T cells from tumor than TDLNs, with tumor-enriched clones also detected in TDLNs. Analysis of scRNA-seq datasets from tumors and JTs of colorectal and non-small cell lung cancer patients, identified a CD8+ terminal exhaustion and a CD8+ pre-exhausted signatures. High expression of exhaustion-associated genes in BC tumors correlated with improved overall survival. Overall, PD-1 expression effectively distinguishes exhaustion stages in CD8+ T cells. PD-1Int cells found in tumors, JTs, and TDLNs represent a promising therapeutic target for cancer immunotherapy.

Hotspots evolution and frontiers of immunotherapy for the treatment of acute myeloid leukemia: A bibliometric analysis

Given the growing significance of immunotherapy in addressing the limitations of conventional acute myeloid leukemia (AML) treatments, this study aimed to elucidate the hotspot evolution and frontiers of immunotherapy in AML using bibliometric analysis. With a strict retrieval strategy applied in the Web of Science Core Collection, 2411 publications were obtained and exported. The temporal and geographical distributions of these publications and the countries, institutions, journals, and authors who contributed to the field were investigated. An in-depth content analysis was performed. The United States had various research institutions dedicated to AML immunotherapy. Frontiers in Immunology had the highest number of publications, but Blood had the highest H-index. Marion Subklewe was the most productive author. The current research hotspots of AML immunotherapy included chimeric antigen receptor-T-cell therapy, antibody-based immunotherapies, immune checkpoint blockade, and combination therapy, highlighting the key aspects of immunotherapy for AML treatment and providing comprehensive insights into the research status and advances in this field. Novel immunotherapies combined with chemotherapy may become the primary focus of AML treatment.

Design, synthesis, and biological evaluation of 2,4-diaminopyrimidine inhibitors of hematopoietic progenitor kinase 1

Cancer immunotherapy is an emerging anti-cancer strategy that enhances immune circulation by targeting the immune system. Among the various targets, HPK1, a member of the mammalian Ste20-like protein serine/threonine kinase family, serves as a crucial negative regulator of immune-mediated mechanisms, positioning it as a promising target for immunotherapy. Herein, based on the reported HPK1 inhibitors characterized by 2,4-diaminopyrimidine components, four series of derivatives were obtained through structural optimization methods. Compound 10c demonstrates significant inhibitory effects on HPK1 kinase, with an IC50 of 0.09 nM. Additionally, it markedly inhibits the phosphorylation of the downstream adaptor protein SLP76, with an IC50 of 33.74 nM, and effectively stimulates the secretion of the T cell activation marker IL-2, exhibiting an EC50 of 84.24 nM. These findings suggest that compound 10c holds considerable promise for applications in immunotherapy.

Synergistic action of combining photodynamic therapy with immunotherapy for eradicating solid tumors in animal models: A systematic review

Malignancies maintain a high rate of mortality worldwide each year, requiring the development of novel therapeutic platforms. Immunotherapy approaches are considered a revolutionary treatment for overcoming malignancies. Photodynamic therapy (PDT) has attracted significant attention in various cancer types. Recent progress in cancer therapies has underscored the potential of combining PDT with immunotherapy. This approach can improve therapeutic outcomes by directly eliminating tumor cells and boosting immune responses for sustained anti-tumor effects in the whole body. This study aims to determine the relative efficacy of combining PDT with immunotherapy compared to PDT alone. Following the PRISMA guidance, an extensive literature review was conducted utilizing Scopus, Web of Science, and PubMed to identify high-quality preclinical studies exploring various aspects of PDT combined with immunotherapy. The adopted PICO framework included studies with rigorous experimental designs and relevant outcomes. The present review reveals the characteristics of tumor models, delivery systems, photosensitizers, and immunotherapy approaches. Key findings indicate that the combined PDT-immunotherapy approach shows promise in treating multiple tumors according to their size, therapeutic biomarkers, and inhibition of distant tumors. Finally, this integrated therapeutic strategy holds significant promise for advancing cancer treatment paradigms by potentiating each treatment efficacy; however, its clinical utility requires careful consideration of the associated challenges.

Plasticity of tumor cell immunogenicity: is it druggable?

This short perspective presents, at a high level, some observations and speculations about cancer immunotherapy that derive from experiences at the Dana-Farber Cancer Institute and the Novartis Institutes of Biomedical Research.

Immunotherapy in gastrointestinal cancers: current strategies and future directions - a literature review

Introduction

The National Cancer Institute defines the disease of "cancer" as a group of disorders in which aberrant cells proliferate uncontrollably and have the potential to infiltrate neighboring tissues. It is well established that cancer remains a significant etiology contributing to worldwide mortality. Gastrointestinal (GI) neoplasms are a type of cancer that affects the digestive system and adds to the total cancer burden. Conventionally, several therapies have been employed, such as radiation and chemotherapy; nevertheless, their adverse effects have prompted the need for an improved therapeutic alternative. Immunotherapy thus became a notable medium of treatment for several malignancies, including tumors of the GI tract.

Aim

This comprehensive review seeks to provide insight on future directions and prospective therapies under development, as well as information regarding the present strategies utilized to mitigate one of the primary forms of cancer, GI cancer.

Methods

A detailed analysis of the existing literature on GI cancers has been conducted. Several databases were employed to gather this information, mainly PubMed/MEDLINE. Different aspects of the disease were considered when searching the databases to provide a comprehensive review of the current and future strategies being incorporated to mitigate the negative consequences of this disease.

Results

Many strategies are being used currently, and some are still under development. These comprise the usage of immune checkpoint inhibitors (ICIs), cytokine therapy, cancer vaccines, oncolytic viruses, and adoptive cell therapy. For instance, various monoclonal antibodies have been developed to inhibit the immunomodulatory effects of programmed death-1 and programmed death-1 ligand. There are also results of several clinical trials showing significant benefits and many changes are introduced to make the best of these strategies and minimize the challenges to group sizes. These challenges include overcoming the tumor's immunosuppressive environment, finding suitable predictive biomarkers, and reducing the adverse effects. Additionally, several novel immunotherapeutic approaches, such as chimeric antigen receptor T-cell (CAR-T) therapy, are being studied. In 2017, the US FDA approved the use of two CAR-T therapies, which marks a major milestone following extensive research and clinical trials. New approaches such as toll-like receptor-directed and helminth-based immunotherapies are being developed for the treatment of GI cancers as well. These therapies, along with targeted treatments, represent the future of immunotherapy in GI cancers.

Conclusion

Immunotherapy plays a significant role in the different types of GI cancers. However, optimizing these treatments will require overcoming barriers such as immune resistance, minimizing side effects, and improving the selection of patients through biomarkers. Continued research into these novel therapies and the mechanisms of immune modulation will be key to maximizing the therapeutic benefits of immunotherapy in the future.

Microdissected tumor cuboids: a microscale cancer model for large-scale testing that retains a complex tumor microenvironment

To bridge the gap between bench and bedside, there is a need for more faithful models of human cancers that can recapitulate key features of the human tumor microenvironment (TME) and simultaneously facilitate large-scale drug tests. Our recently developed microdissection method optimizes the yield of large numbers of cuboidal microtissues (″cuboids″, ~(400 µm) 3 ) from a tumor biopsy. Here we demonstrate that cuboids from syngeneic mouse tumor models and human tumors retain a complex TME, making them amenable for drug and immunotherapy evaluation. We characterize relevant TME parameters, such as cellular architecture, cytokine secretion, proteomics profiles, and response to drug panels in multi-well arrays. Despite the cutting procedure and the time spent in culture (up to 7 days), the cuboids display strong cytokine expression and drug responses, including to immunotherapy. Overall, our results suggest that cuboids could provide essential therapeutic information for personalized oncology applications and could help the development of TME-dependent therapeutics and cancer disease models, including for clinical trials.

Clinical Progresses and Challenges of Bispecific Antibodies for the Treatment of Solid Tumors

In recent years, bispecific antibodies (BsAbs) have emerged as a promising therapeutic strategy against tumors. BsAbs can recruit and activate immune cells, block multiple signaling pathways, and deliver therapeutic payloads directly to tumor sites. This review provides a comprehensive overview of the recent advances in the development and clinical application of BsAbs for the treatment of solid tumors. We discuss the different formats, the unique mechanisms of action, and the clinical outcomes of the most advanced BsAbs in solid tumor therapy. Several studies have also analyzed the clinical progress of bispecific antibodies. However, this review distinguishes itself by exploring the challenges associated with bispecific antibodies and proposing potential solutions. As the field progresses, BsAbs hold promise to redefine cancer treatment paradigms and offer new hope to patients with solid tumors.

Label-free, real-time monitoring of cytochrome C drug responses in microdissected tumor biopsies with a multi-well aptasensor platform

Functional assays on intact tumor biopsies can complement genomics-based approaches for precision oncology, drug testing, and organs-on-chips cancer disease models by capturing key therapeutic response determinants, such as tissue architecture, tumor heterogeneity, and the tumor microenvironment. Most of these assays rely on fluorescent labeling, a semiquantitative method best suited for single-time-point assays or labor-intensive immunostaining analysis. Here, we report integrated aptamer electrochemical sensors for on-chip, real-time monitoring of cytochrome C, a cell death indicator, from intact microdissected tissues with high affinity and specificity. The platform features a multi-well sensor layout and a multiplexed electronic setup. The aptasensors measure increases in cytochrome C in the supernatant of mouse or human microdissected tumors after exposure to various drug treatments. Because of the sensor's high affinity, it primarily tracks rising concentrations of cytochrome C, capturing dynamic changes during apoptosis. This approach could help develop more advanced cancer disease models and apply to other complex in vitro disease models, such as organs-on-chips and organoids.

Stem cell-based targeted therapy in pancreatic cancer: Current approaches and future prospects

Despite recent improvements in oncology, diagnosis, and therapy, pancreatic cancer remains extremely difficult to cure due to its aggressive growth pattern with early invasion and distant metastases, chemoresistance, and a lack of effective screening modalities for early detection. Here, novel therapeutic approaches for treating pancreatic cancer are urgently needed. Recently, stem cells have drawn a lot of interest as a possible treatment for pancreatic cancer due to their ability to locate tumors. Though research over the last few decades has revealed some very exciting and promising new treatment approaches, the clinical success of these stem-cell based anti-cancer medicines has been quite limited. The most effective stem cell-mediated therapeutic options will only be available with a deeper understanding of the intricate molecular biology underlying pancreatic cancer and the subsequent identification of cancer stem cells as a novel target that promotes the growth of the cancer and resistance to chemotherapy. This review will highlight the stem cell based anti-cancer therapy targeting pancreatic cancer stem cells and different molecular signaling pathways. A particular focus will be on the therapeutic potential of naïve Stem cells, anti-cancer drug loaded stem cells, genetically engineered stem cells and exosomal miRNA released by stem cells in pancreatic cancer treatment. Similarly, the role of nanotechnology in stem cell based anticancer therapy will be further discussed to better implementation of these cell-based cancer therapy.

NF2: An underestimated player in cancer metabolic reprogramming and tumor immunity

Neurofibromatosis type 2 (NF2) is a tumor suppressor gene implicated in various tumors, including mesothelioma, schwannomas, and meningioma. As a member of the ezrin, radixin, and moesin (ERM) family of proteins, merlin, which is encoded by NF2, regulates diverse cellular events and signalling pathways, such as the Hippo, mTOR, RAS, and cGAS-STING pathways. However, the biological role of NF2 in tumorigenesis has not been fully elucidated. Furthermore, cross-cancer mutations may exert distinct biological effects on tumorigenesis and treatment response. In addition to the functional inactivation of NF2, the codeficiency of other genes, such as cyclin-dependent kinase inhibitor 2A/B (CDKN2A/B), BRCA1-associated protein-1 (BAP1), and large tumor suppressor 2 (LATS2), results in unique tumor characteristics that should be considered in clinical treatment decisions. Notably, several recent studies have explored the metabolic and immunological features associated with NF2, offering potential insights into tumor biology and the development of innovative therapeutic strategies. In this review, we consolidate the current knowledge on NF2 and examine the potential connection between cancer metabolism and tumor immunity in merlin-deficient malignancies. This review may provide a deeper understanding of the biological roles of NF2 and guide possible therapeutic avenues.

Drug testing of monodisperse arrays of live microdissected tumors using a valved multiwell microfluidic platform

Cancer drug testing in animals is an extremely poor predictor of the drug's safety and efficacy observed in humans. Hence there is a pressing need for functional testing platforms that better predict traditional and immunotherapy responses in human, live tumor tissue or tissue constructs, and at the same time are compatible with the use of mouse tumor tissue to facilitate building more accurate disease models. Since many cancer drug actions rely on mechanisms that depend on the tumor microenvironment (TME), such platforms should also retain as much of the native TME as possible. Additionally, platforms based on miniaturization technologies are desirable to reduce animal use and sensitivity to human tissue scarcity. Present high-throughput testing platforms that have some of these features, e.g. based on patient-derived tumor organoids, require a growth step that alters the TME. On the other hand, microdissected tumors (μDTs) or "spheroids" that retain an intact TME have shown promising responses to immunomodulators acting on native immune cells. However, difficult tissue handling after microdissection has reduced the throughput of drug testing on μDTs, thereby constraining the inherent advantages of producing numerous TME-preserving units of tissue for drug testing. Here we demonstrate a microfluidic 96-well platform designed for drug treatment of hundreds of similarly-sized, cuboidal μDTs ("cuboids") produced from a single tumor sample. The platform organizes a monodisperse array of four cuboids per well in 384 hydrodynamic traps. The microfluidic device, entirely fabricated in thermoplastics, features 96 microvalves that fluidically isolate each well after the cuboid loading step for straightforward multi-drug testing. Since our platform makes the most of scarce tumor tissue, it can potentially be applied to human biopsies that preserve the human TME while minimizing animal testing.

Bridging the divide: unveiling mutual immunological pathways of cancer and pregnancy

The juxtaposition of two seemingly disparate physiological phenomena within the human body-namely, cancer and pregnancy-may offer profound insights into the intricate interplay between malignancies and the immune system. Recent investigations have unveiled striking similarities between the pivotal processes underpinning fetal implantation and successful gestation and those governing tumor initiation and progression. Notably, a confluence of features has emerged, underscoring parallels between the microenvironment of tumors and the maternal-fetal interface. These shared attributes encompass establishing vascular networks, cellular mobilization, recruitment of auxiliary tissue components to facilitate continued growth, and, most significantly, the orchestration of immune-suppressive mechanisms.Our particular focus herein centers on the phenomenon of immune suppression and its protective utility in both of these contexts. In the context of pregnancy, immune suppression assumes a paramount role in shielding the semi-allogeneic fetus from the potentially hostile immune responses of the maternal host. In stark contrast, in the milieu of cancer, this very same immunological suppression fosters the transformation of the tumor microenvironment into a sanctuary personalized for the neoplastic cells.Thus, the striking parallels between the immunosuppressive strategies deployed during pregnancy and those co-opted by malignancies offer a tantalizing reservoir of insights. These insights promise to inform novel avenues in the realm of cancer immunotherapy. By harnessing our understanding of the immunological events that detrimentally impact fetal development, a knowledge grounded in the context of conditions such as preeclampsia or miscarriage, we may uncover innovative immunotherapeutic strategies to combat cancer.

Molecular Engineering of Electrosprayed Hydrogel Microspheres to Achieve Synergistic Anti-Tumor Chemo-Immunotherapy with ACEA Cargo

Molecular engineering of drug delivering platforms to provide collaborative biological effects with loaded drugs is of great medical significance. Herein, cannabinoid receptor 1 (CB1)- and reactive oxygen species (ROS)-targeting electrosprayed microspheres (MSs) are fabricated by loading with the CB1 agonist arachidonoyl 2'-chloroethylamide (ACEA) and producing ROS in a photoresponsive manner. The synergistic anti-tumor effects of ACEA and ROS released from the MSs are assessed. ACEA inhibits epidermal growth factor receptor signaling and altered tumor microenvironment (TME) by activating CB1 to induce tumor cell death. The MSs are composed of glycidyl methacrylate-conjugated xanthan gum (XGMA) and Fe3+, which form dual molecular networks based on a Fe3+-(COO-)3 network and a C═C addition reaction network. Interestingly, the Fe3+-(COO-)3 network can be disassembled instantly under the conditions of lactate sodium and ultraviolet exposure, and the disassembly is accompanied by massive ROS production, which directly injures tumor cells. Meanwhile, the transition of dual networks to a single network boosts the ACEA release. Together, the activities of the ACEA and MSs promote immunogenic tumor cell death and create a tumor-suppressive TME by increasing M1-like tumor-associated macrophages and CD8+ T cells. In summation, this study demonstrates strong prospects of improving anti-tumor effects of drug delivering platforms through molecular design.

Ag85B-ENO146-82 therapeutic vaccines enhance anti-tumor immunity by inducing CD8+ T cells and remodeling tumor microenvironment

Lung cancer is the leading cause of cancer-related morbidity and mortality in China. However, the effect of traditional cancer treatment is limited. Herein, we designed a therapeutic cancer vaccine based on the tumor-associated antigen mENO1, which can prevent lung cancer growth in vivo, and explored the underlying mechanism of Ag85B-ENO146-82 therapy. Lewis lung carcinoma (LLC) tumor-bearing immunocompetent C57BL/6 mice that received Ag85B-ENO146-82 treatment showed antitumor effect. Further, we detected CD8+ T, CD4+ T in LLC-bearing C57BL/6 mice to understand the impact of Ag85B-ENO146-82 therapy on antitumor capacity. The Ag85B-ENO146-82 therapy induced intensive infiltration of CD4+ and CD8+ T cells in tumors, increased tumor-specific IFN-γ and TNF-α secretion by CD8+ T cells and promoted macrophage polarization toward M1 phenotype. Flow cytometric analysis revealed that CD8+ T effector memory (TEM) cells and central memory (TCM) cells were upregulated. qPCR and ELISA analysis showed that the expression of IFN-γ and TNF-α were upregulated, whereas of IL1β, IL6 and IL10 were downregulated. This study demonstrated that Ag85B-ENO146-82 vaccine augmented antitumor efficacy, which was CD8+ T cells dependent. Our findings paved the way for therapeutic tumor-associated antigen peptide vaccines to enhance anti-tumor immunotherapy for treatment of cancer.

Label-Free, Real-Time Monitoring of Cytochrome C Responses to Drugs in Microdissected Tumor Biopsies with a Multi-Well Aptasensor Platform

Functional assays on intact tumor biopsies can potentially complement and extend genomics-based approaches for precision oncology, drug testing, and organs-on-chips cancer disease models by capturing key determinants of therapeutic response, such as tissue architecture, tumor heterogeneity, and the tumor microenvironment. Currently, most of these assays rely on fluorescent labeling, a semi-quantitative method best suited to be a single-time-point terminal assay or labor-intensive terminal immunostaining analysis. Here, we report integrated aptamer electrochemical sensors for on-chip, real-time monitoring of increases of cytochrome C, a cell death indicator, from intact microdissected tissues with high affinity and specificity. The platform features a multi-well sensor layout and a multiplexed electronic setup. The aptasensors measure increases in cytochrome C in the supernatant of mouse or human microdissected tumors after exposure to various drug treatments. Since the aptamer probe can be easily exchanged to recognize different targets, the platform could be adapted for multiplexed monitoring of various biomarkers, providing critical information on the tumor and its microenvironment. This approach could not only help develop more advanced cancer disease models but also apply to other complex in vitro disease models, such as organs-on-chips and organoids.

Novel immune checkpoint targets: A promising therapy for cancer treatments

The immune system frequently comprises immunological checkpoints. They serve as a barrier to keep the immune system from overreacting and damaging cells that are robust. Immune checkpoint inhibitors (ICIs) are utilized in immunotherapy to prevent the synergy of partner proteins of checkpoint proteins with auxiliary proteins. Moreover, the T cells may target malignant cells since the "off" signal cannot be conveyed. ICIs, which are mostly composed of monoclonal antibodies (mAbs) against cytotoxic T lymphocyte-associated antigen-4 (CTLA-4) and anti- programmed death-1/programmed ligand 1 (anti-PD-1/PD-L1), might transform the context of cancer therapy. Further, more patients continued to exhibit adaptive resistance, even though several ICIs demonstrated convincing therapeutic benefits in selective tumor types. Immune checkpoint therapy's overall effectiveness is still lacking at this time. A popular area of study involves investigating additional immune checkpoint molecules. Recent research has found a number of fresh immune checkpoint targets, including NKG2A ligands, TIGIT, B7-H6 ligands, Galectin 3, TIM3, and so on. These targets have been focus of the study, and recent investigational approaches have shown encouraging outcomes. In this review article, we covered the development and present level understanding of these recently identified immune checkpoint molecules, its effectiveness and limitations.

Gastrointestinal mucosal toxicities from immune checkpoint inhibitors: Current understanding and future directions

Immune checkpoint inhibitor (ICI) therapy has revolutionized the field of oncology over the past decade, leading to durable remissions in some patients but also producing a wide spectrum of treatment-limiting inflammatory toxicities that are referred to as immune-related adverse events (irAEs). Although irAEs can involve any organ system in the body, they most commonly affect the barrier tissues, including the gastrointestinal tract with colitis and enterocolitis affecting a significant fraction of patients on ICIs. We are beginning to understand the mechanisms that drive ICI colitis, with early experiments indicating a role for CD8+ resident memory T cells (TRMs) in the gut, which become activated and differentiate into cytotoxic cells in response to ICI therapy. The risk factors that define who will develop ICI colitis are not understood and substantial efforts are underway to identify potential biomarkers for risk of this and other toxicities. Optimal management of ICI colitis is also an area of active investigation. Current standard treatments are based largely on small, retrospective analyses, and while drugs like systemic glucocorticoids or the TNFα inhibitor infliximab do appear to be highly active in ICI colitis, the impact of these therapies on antitumor responses is poorly understood. As discussed in this review, future work will have to define the immune mechanisms driving ICI colitis in more detail and in comparison to antitumor responses in order to identify candidate pathways that can be targeted to improve ICI colitis without interfering in antitumor immunity. Studying these interventions will require randomized, controlled trials with both tumor and colitis endpoints, a goal that will necessitate collaboration across institutions and funding agencies. We are at a point where such collaborative trials are feasible, and have the potential to greatly improve the care of patients with ICI colitis as well as other irAEs.

Blockade of innate inflammatory cytokines TNF, IL-1, or IL-6 overcomes virotherapy-induced cancer equilibrium to promote tumor regression

Cancer therapeutics can lead to immune equilibrium in which the immune response controls tumor cell expansion without fully eliminating the cancer. The factors involved in this equilibrium remain incompletely understood, especially those that would antagonize the anti-tumor immune response and lead to tumor outgrowth. We previously demonstrated that continuous treatment with a non-replicating herpes simplex virus 1 expressing interleukin (IL)-12 induces a state of cancer immune equilibrium highly dependent on interferon-γ. We profiled the IL-12 virotherapy-induced immune equilibrium in murine melanoma, identifying blockade of innate inflammatory cytokines, tumor necrosis factor alpha (TNFα), IL-1β, or IL-6 as possible synergistic interventions. Antibody depletions of each of these cytokines enhanced survival in mice treated with IL-12 virotherapy and helped to overcome equilibrium in some tumors. Single-cell RNA-sequencing demonstrated that blockade of inflammatory cytokines resulted in downregulation of overlapping inflammatory pathways in macrophages, shifting immune equilibrium towards tumor clearance, and raising the possibility that TNFα blockade could synergize with existing cancer immunotherapies.

Mesoporous silica/organosilica nanoparticles for cancer immunotherapy

Cancer is one of the fatal diseases in the history of humankind. In this regard, cancer immunotherapeutic strategies have revolutionized the traditional mode of cancer treatment. Silica based nano-platforms have been extensively applied in nanomedicine including cancer immunotherapy. Mesoporous silica nanoparticles (MSN) and mesoporous organosilica nanoparticles (MON) are attractive candidates due to the ease in controlling the structural parameters as needed for the targeted immunotherapeutic applications. Especially, the MON provide an additional advantage of controlling the composition and modulating the biological functions to actively synergize with other immunotherapeutic strategies. In this review, the applications of MSN, MON, and metal-doped MSN/MON in the field of cancer immunotherapy and tumor microenvironment regulation are comprehensively summarized by highlighting the structural and compositional attributes of the silica-based nanoplatforms.

Concurrent immune checkpoint inhibition and selective immunosuppressive therapy in patients with immune-related enterocolitis

PURPOSE

Immune checkpoint inhibitor (ICI) therapy is often suspended because of immune-related enterocolitis (irEC). We examined the effect of resumption of ICIs with or without concurrent selective immunosuppressive therapy (SIT) on rates of symptom recurrence and survival outcomes.

METHODS

This retrospective, multicenter study examined patients who were treated with ICI and developed irEC requiring SIT (infliximab or vedolizumab) for initial symptom control or to facilitate steroid tapering between May 2015 and June 2020. After symptom resolution, patients were restarted either on ICI alone or on concurrent ICI and SIT at the discretion of the treating physicians. The associations between irEC recurrence and treatment group were assessed via univariate analyses and multivariate logistic regression. Cox proportional hazards model was used for survival analysis.

RESULTS

Of the 138 included patients who required SIT for initial irEC symptom control, 61 (44.2%) patients resumed ICI without concurrent SIT (control group) and 77 (55.8%) patients resumed ICI therapy with concurrent SIT: 33 with infliximab and 44 with vedolizumab. After symptom resolution, patients in the control group were more commonly restarted on a different ICI regimen (65.6%) compared with those receiving SIT (31.2%) (p<0.001). The total number of ICI doses administered after irEC resolution and ICI resumption was similar in both groups (four to five doses). Recurrence of severe colitis or diarrhea after ICI resumption was seen in 34.4% of controls compared with 20.8% of patients receiving concurrent SIT. Concurrent SIT was associated with reduced risk of severe irEC recurrence after ICI resumption in a multivariate logistic regression model (OR 0.34; 95% CI 0.13 to 0.92; p=0.034). There was no difference in survival outcomes between patients in the control group and patients concurrently treated with SIT.

CONCLUSION

After resolution of irEC symptoms, reinitiation of ICI with concurrent SIT is safe, reduces severe irEC recurrence, and has no negative impact on survival outcomes.

Can Immune Therapy Cure Acute Myeloid Leukemia?

OPINION STATEMENT

Although safe and effective immune therapies have been developed in several cancers, this has not been so in acute myeloid leukaemia (AML). Studies of antibodies to CD33, CD123 and CLL-1 report with unconvincing efficacy and substantial adverse events. Lacking AML-specific target antigens, these approaches using non-specific antigen targets often cause unacceptable bone marrow toxicity and off-target adverse events. Studies of AML incidence in persons with immune deficiency indicate little if any immune surveillance against AML. In contrast, data studies of recipients of haematopoietic cell transplants support an effective allogeneic anti-AML effect associated with graft-versus-host disease (GvHD) and possibly a specific graft-versus-leukaemia (GvL) effect. A special problem in the immune therapy of AML is few neo-antigens compared with solid cancers because of a relatively low mutation frequency. Studies of CAR-T-, CAR-NK-adaptor CAR-T- and allogeneic NK-cells are progressing as are approaches using synthetic biology. Presently, there are no convincing data of efficacy of immune therapy in AML.

Cas12a/Cpf1 knock-in mice enable efficient multiplexed immune cell engineering

Cas9 transgenic animals have drastically accelerated the discovery of novel immune modulators. But due to its inability to process its own CRISPR RNAs (crRNAs), simultaneous multiplexed gene perturbations using Cas9 remains limited, especially by pseudoviral vectors. Cas12a/Cpf1, however, can process concatenated crRNA arrays for this purpose. Here, we created conditional and constitutive LbCas12a knock-in transgenic mice. With these mice, we demonstrated efficient multiplexed gene editing and surface protein knockdown within individual primary immune cells. We showed genome editing across multiple types of primary immune cells including CD4 and CD8 T cells, B cells, and bone-marrow derived dendritic cells. These transgenic animals, along with the accompanying viral vectors, together provide a versatile toolkit for a broad range of ex vivo and in vivo gene editing applications, including fundamental immunological discovery and immune gene engineering.

Artificial intelligence in cancer immunotherapy: Applications in neoantigen recognition, antibody design and immunotherapy response prediction

Cancer immunotherapy is a method of controlling and eliminating tumors by reactivating the body's cancer-immunity cycle and restoring its antitumor immune response. The increased availability of data, combined with advancements in high-performance computing and innovative artificial intelligence (AI) technology, has resulted in a rise in the use of AI in oncology research. State-of-the-art AI models for functional classification and prediction in immunotherapy research are increasingly used to support laboratory-based experiments. This review offers a glimpse of the current AI applications in immunotherapy, including neoantigen recognition, antibody design, and prediction of immunotherapy response. Advancing in this direction will result in more robust predictive models for developing better targets, drugs, and treatments, and these advancements will eventually make their way into the clinical setting, pushing AI forward in the field of precision oncology.

A Comprehensive View of the Cancer-Immunity Cycle (CIC) in HPV-Mediated Cervical Cancer and Prospects for Emerging Therapeutic Opportunities

Cervical cancer (CC) is the fourth most common cancer in women worldwide, with more than 500,000 new cases each year and a mortality rate of around 55%. Over 80% of these deaths occur in developing countries. The most important risk factor for CC is persistent infection by a sexually transmitted virus, the human papillomavirus (HPV). Conventional treatments to eradicate this type of cancer are accompanied by high rates of resistance and a large number of side effects. Hence, it is crucial to devise novel effective therapeutic strategies. In recent years, an increasing number of studies have aimed to develop immunotherapeutic methods for treating cancer. However, these strategies have not proven to be effective enough to combat CC. This means there is a need to investigate immune molecular targets. An adaptive immune response against cancer has been described in seven key stages or steps defined as the cancer-immunity cycle (CIC). The CIC begins with the release of antigens by tumor cells and ends with their destruction by cytotoxic T-cells. In this paper, we discuss several molecular alterations found in each stage of the CIC of CC. In addition, we analyze the evidence discovered, the molecular mechanisms and their relationship with variables such as histological subtype and HPV infection, as well as their potential impact for adopting novel immunotherapeutic approaches.

Discovery of Macrocycle-Based HPK1 Inhibitors for T-Cell-Based Immunotherapy

Hematopoietic progenitor kinase 1 (HPK1) is a negative regulator of T-cell activation, and targeting HPK1 is considered a promising strategy for improving responses to antitumor immune therapies. The biggest challenge of HPK1 inhibitor design is to achieve a higher selectivity to GLK, an HPK1 homology protein as a positive regulator of T-cell activation. Herein, we report the design of a series of macrocycle-based HPK1 inhibitors via a conformational constraint strategy. The identified candidate compound 5i exhibited HPK1 inhibition with an IC₅₀ value of 0.8 nM and 101.3-fold selectivity against GLK. Compound 5i also displayed good oral bioavailability (F = 27-49%) in mice and beagles and favorable metabolic stability (T_1/2 > 186.4 min) in human liver microsomes. More importantly, compound 5i demonstrated a clear synergistic effect with anti-PD-1 in both MC38 (MSI) and CT26 (MSS) syngeneic tumor mouse models. These results showed that compound 5i has a great potential in immunotherapy.

Update on Immune Checkpoint Inhibitor Enterocolitis

PURPOSE OF REVIEW

Immune checkpoint inhibitor (ICI) therapy revolutionized the treatment of multiple solid and hematologic malignancies. Yet, with it came profound inflammatory toxicities that mimic autoimmune diseases, termed immune-related adverse events (irAEs). Prominent among these is gastrointestinal inflammation, including a spectrum of gastritis, enteritis, and colitis. Here we synthesize an approach to immune checkpoint related enterocolitis (irEC) - including diagnostics and therapeutics - underpinned by new insights into the mechanism behind these phenomena.

RECENT FINDINGS

This review presents updated insights on how to approach irEC, including novel approaches to selective immunosuppressive therapy, the role of fecal microbiota transplant, and the underlying cellular mechanisms of irEC. This review provides an update on irEC diagnosis and therapy, with considerations of new therapies and special patient populations. The field of gastrointestinal irAEs requires additional investigation, which will ultimately provide the tools required for patients to continue to receive life-saving ICI therapy.

Homotypic Targeted Photosensitive Nanointerferer for Tumor Cell Cycle Arrest to Boost Tumor Photoimmunotherapy

Recent advances in tumor immunotherapy mainly tend to remodel the immunosuppressive tumor microenvironment (TME) for immune enhancement. However, the complexity of TME makes it unlikely to achieve satisfactory therapeutic effects with any single intervention alone. Here, we focus on exposing intrinsic features of tumor cells to trigger direct pleiotropic antitumor immunity. We develop a photosensitive nanointerferer that is engineered with a nanoscale metal-organic framework decorated with tumor cell membranes for targeted delivery of a photosensitizer and small interfering RNA, which is used to knock down cyclin-dependent kinase 4 (Cdk4). Cdk4 blockade can arrest the cell cycle of tumor cells to facilitate antigen exposure and increase the expression level of programmed cell death protein ligand 1 (PD-L1). Under laser irradiation, photodynamic damage triggered by the nanointerferer induces the release of tumor antigens and recruitment of dendritic cells (DCs), thereby promoting the antitumor activity of CD8⁺ T cells in combination with anti-PD-L1 antibodies. Ultimately, these events markedly retard tumor progression in a mouse model of ectopic colon tumor with negligible adverse effects. This study provides an alternative treatment for effective antitumor immunity by exciting the intrinsic potential of tumor cells to initiate immune responses while reducing immune-related toxicities.

mRNA-Based Approaches to Treating Liver Diseases

Diseases that affect the liver account for approximately 2 million deaths worldwide each year. The increasing prevalence of these diseases and the limited efficacy of current treatments are expected to stimulate substantial growth in the global market for therapeutics that target the liver. Currently, liver transplantation is the only curative option available for many liver diseases. Gene therapy represents a valuable approach to treatment. The liver plays a central role in a myriad of essential metabolic functions, making it an attractive organ for gene therapy; hepatocytes comprise the most relevant target. To date, viral vectors constitute the preferred approach to targeting hepatocytes with genes of therapeutic interest. Alternatively, mRNA-based therapy offers a number of comparative advantages. Clinical and preclinical studies undertaken to treat inherited metabolic diseases affecting the liver, cirrhosis and fibrosis, hepatocellular carcinoma, hepatitis B, and cytomegalovirus using lipid nanoparticle-encapsulated mRNAs that encode the therapeutic or antigenic protein of interest are discussed.

PEGylation of Goldbody: PEG-aided conformational engineering of peptides on gold nanoparticles

It is still a great challenge to engineer flexible non-functional molecules into special conformations to carry out novel functions. Previously, we successfully restored the native conformations and functions of the flexible complementary-determining regions (CDRs) of antibodies on the surface of gold nanoparticles (AuNPs), and created a class of AuNP-based artificial antibodies, denoted as Goldbodies. Yet, in these Goldbodies, there are dozens of CDRs on one Goldbody. Herein, we show that the number of CDRs per Goldbody could be reduced by more than one order of magnitude, by replacing the majority of the CDRs with polyethylene glycol (PEG) with a molecular weight around 600 Da, while the native conformations and functions of the CDRs could still be restored on AuNPs. Also, we find that the PEG with two terminal -SH groups is much better than the PEG with a single -SH group for aiding the restoration of the native conformation of the CDRs on AuNPs. To demonstrate the potential generic applicability of the PEGylation in aiding conformational engineering of peptides, two PEGylated Goldbodies have been created, which can specifically recognize lysozyme and epidermal growth factor receptor, respectively. The PEGylated Goldbodies further prove the mechanism of conformational engineering and the "Confined Lowest Energy Fragments" (CLEFs) hypothesis, and pave the way for future applications of Goldbodies.

Tumor cells dictate anti-tumor immune responses by altering pyruvate utilization and succinate signaling in CD8+ T cells

The tumor microenvironment (TME) is a unique metabolic niche that can inhibit T cell metabolism and cytotoxicity. To dissect the metabolic interplay between tumors and T cells, we establish an in vitro system that recapitulates the metabolic niche of the TME and allows us to define cell-specific metabolism. We identify tumor-derived lactate as an inhibitor of CD8+ T cell cytotoxicity, revealing an unexpected metabolic shunt in the TCA cycle. Metabolically fit cytotoxic T cells shunt succinate out of the TCA cycle to promote autocrine signaling via the succinate receptor (SUCNR1). Cytotoxic T cells are reliant on pyruvate carboxylase (PC) to replenish TCA cycle intermediates. By contrast, lactate reduces PC-mediated anaplerosis. The inhibition of pyruvate dehydrogenase (PDH) is sufficient to restore PC activity, succinate secretion, and the activation of SUCNR1. These studies identify PDH as a potential drug target to allow CD8+ T cells to retain cytotoxicity and overcome a lactate-enriched TME.

An in situ hydrogel-mediated chemo-immunometabolic cancer therapy

Metabolic reprogramming of the tumor microenvironment (TME) and poor immunogenicity are two of the challenges that cancer immunotherapies have to overcome for improved clinical benefits. Among various immunosuppressive metabolites that keep anti-tumor immunity in check, the tryptophan catabolite kynurenine (Kyn) is an attractive target for blockade given its role in mediating immunosuppression through multiple pathways. Here, we present a local chemo-immunometabolic therapy through injection of a supramolecular hydrogel concurrently releasing doxorubicin that induces immunogenic tumor cell death and kynureninase that disrupts Kyn-mediated immunosuppressive pathways in TME. The combination synergically enhances tumor immunogenicity and unleashes anti-tumor immunity. In mouse models of triple negative breast cancer and melanoma, a single low dose peritumoral injection of the therapeutic hydrogel promotes TME transformation toward more immunostimulatory, which leads to enhanced tumor suppression and extended mouse survival. In addition, the systemic anti-tumor surveillance induced by the local treatment exhibits an abscopal effect and prevents tumor relapse post-resection. This versatile approach for local chemo-immunometabolic therapy may serve as a general strategy for enhancing anti-tumor immunity and boosting the efficacy of cancer immunotherapies.

Folding of Flexible Protein Fragments and Design of Nanoparticle-Based Artificial Antibody Targeting Lysozyme

It is generally believed that a protein's sequence solely determines its native structure, but how the long- and short-range interactions jointly determine the native structure/conformation of the protein or every local fragment of the protein is still not fully understood. Since most protein fragments are unstructured on their own, direct observation of the folding of flexible protein fragments is very difficult. Interestingly, we show that it is possible to graft the complementary-determining regions (CDRs) of antibodies onto the surface of a gold nanoparticle (AuNP) to create AuNP-based artificial antibodies (denoted as Goldbodies), such as an antilysozyme Goldbody. Goldbodies can specifically recognize the corresponding antigens like the original natural antibodies do, but direct structural evidence for the refolding or restoration of native conformation of the grafted CDRs on AuNPs is still missing and in high demand. Herein we design a new Goldbody that targets an epitope on the lysozyme different from that of the previous antilysozyme Goldbody, and the one circle of helix in the CDR makes it possible to distinguish the unfolded conformation of the free CDR and its folded conformation on AuNPs by circular dichroism (CD) spectroscopy. The refolding of flexible protein fragments on NPs provides unique evidence and inspiration for understanding the fundamental principles of protein folding.

Dendritic cells can prime anti-tumor CD8+ T cell responses through major histocompatibility complex cross-dressing

Antigen cross-presentation, wherein dendritic cells (DCs) present exogenous antigen on major histocompatibility class I (MHC-I) molecules, is considered the primary mechanism by which DCs initiate tumor-specific CD8+ T cell responses. Here, we demonstrate that MHC-I cross-dressing, an antigen presentation pathway in which DCs acquire and display intact tumor-derived peptide:MHC-I molecules, is also important in orchestrating anti-tumor immunity. Cancer cell MHC-I expression was required for optimal CD8+ T cell activation in two subcutaneous tumor models. In vivo acquisition of tumor-derived peptide:MHC-I molecules by DCs was sufficient to induce antigen-specific CD8+ T cell priming. Transfer of tumor-derived human leukocyte antigen (HLA) molecules to myeloid cells was detected in vitro and in human tumor xenografts. In conclusion, MHC-I cross-dressing is crucial for anti-tumor CD8+ T cell priming by DCs. In addition to quantitatively enhancing tumor antigen presentation, MHC cross-dressing might also enable DCs to more faithfully and efficiently mirror the cancer cell peptidome.

A degron system targeting endogenous PD-1 inhibits the growth of tumor cells in mice

Recently, targeted protein degradation systems have been developed using the ubiquitin-proteasome system. Here, we established Programmed cell death-1 (PD-1) knockdown mice as a model system for subjecting endogenous mouse proteins to the small molecule-assisted shutoff (SMASh) degron system. SMASh degron-tagged PD-1-mCherry in Jurkat cells and CD3+ splenocytes were degraded by the NS3/4A protease inhibitors, asunaprevir (ASV) or grazoprevir (GRV). Growth of MC-38 colon adenocarcinoma cells injected in Pdcd1-mCherry-SMASh homozygous knock-in (KI) mice was repressed by ASV or GRV. Moreover, growth of MC-38 cells was suppressed in wild-type mice transplanted with KI bone marrow cells after GRV treatment. This is the first study to use a degron tag targeting an endogenous mouse protein in vivo. Our experimental system using the SMASh degron may be employed for treating diseases and characterizing the cellular functions of essential proteins.

Overview of Checkpoint Inhibitors Mechanism of Action: Role of Immune-Related Adverse Events and Their Treatment on Progression of Underlying Cancer

In recent years, immunotherapy-based regimens have been included into the treatment's algorithm of several cancer types. Programmed death-1 (PD-1) and cytotoxic T lymphocyte antigen-4 (CTLA-4) interact with their ligands found on the surface of antigen presenting cells (APC) or tumor cells (PD-L1/2 and CD80/86). Through these interactions, stimulatory or inhibitory signals are established. Immune checkpoint inhibitors (ICIs), block these interactions, and when administered not only as monotherapy but also as part of combination regimens, have shown to improve survival results in multiple advanced cancers leading to an increasing number of patients treated with ICI and, as a consequence, a rise in the number of patients developing immune-related adverse events (irAEs). Presence of irAEs has been associated with greater benefit from treatment, especially when blocking PD-L1. Recent data suggests that treatment benefit persists after discontinuation of ICIs due to a treatment related adverse event, regardless of the grade. Patients experiencing grade 3-4 irAEs are at risk of toxicity recurrence after reintroducing immunotherapy and therefore, the decision to resume the treatment is challenging. In these cases, a multidisciplinary approach is always needed and several factors should be considered. Management of severe toxicities may require systemic corticosteroids which can impact on T-cell function. Due to their immunosuppressive properties, it is necessary to deeper determine how corticosteroids influence responses. In terms of overall survival (OS), the use of steroids as therapy for irAEs seems not to reduce OS and several studies have reported durable responses in patients experiencing autoimmune toxicities treated with corticosteroids.

Traversing through the Dynamic Protein-Protein Interaction Landscape and Conformational Plasticity of PD-1 for Small-Molecule Discovery

Monoclonal antibodies (mAbs) blocking the PD-1/PD-L1 interface have shown remarkable success in treating malignancies, but they may also initiate lethal immune-related adverse events. Small molecules may circumvent the mAb limitations; however, none has entered clinical trials targeting PD-1. Its complex protein-protein interaction interfaces necessitate an atomic-level understanding of recognition and binding mechanisms. Hence, we have aimed to highlight the PD-1's sequence-structure-dynamic-function link with its cognate ligands and diversely reported inhibitors. We focus primarily on the anti-PD-1 mAbs, their mode of actions, and interactions with PD-1 epitopes. The comparison of co-crystals showed that these ligands/inhibitors harness the PD-1's conformational plasticity and structural determinants differentially. The relationship between modulator binding patterns and biological activity is demonstrated using interaction fingerprinting of all reported human PD-1 co-crystals. The significant dynamical events and hot-spot residues underpinned from crystallographic wealth and computational studies have been highlighted to expedite small-molecule discovery.

Translational advances in pancreatic ductal adenocarcinoma therapy

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive cancer that is most frequently detected at advanced stages, limiting treatment options to systemic chemotherapy with modest clinical responses. Here, we review recent advances in targeted therapy and immunotherapy for treating subtypes of PDAC with diverse molecular alterations. We focus on the current preclinical and clinical evidence supporting the potential of these approaches and the promise of combinatorial regimens to improve the lives of patients with PDAC.

Identification of the Marine Alkaloid Lepadin A as Potential Inducer of Immunogenic Cell Death

Natural products and their synthetic analogs and derivatives are a traditional source of bioactive molecules with potential development as drug candidates. In this context, Marine Natural Products (MNPs) represent a rich reservoir of diverse molecular skeletons with potential pharmacological activity that, so far, has been mostly explored in cancer and infectious diseases. Starting from the development of a novel bioassay-guided screening platform for immunomodulatory compounds from an in-house MNPs library, we report the identification of the alkaloid lepadin A as a new model compound for immune-based anticancer activity with characteristics that suggest a possible mechanism as Immunogenic Cell Death inducer. The work describes the molecular-based bioprospecting in the Gulf of Naples together with the bioassay-guided fractionation, the chemical characterization of the alkaloid, and the biological activity in mouse dendritic cells (D1).

Immunotherapies for hepatocellular carcinoma

Cases of hepatocellular carcinoma (HCC) are rapidly rising. This is particularly the case in the Western world, as a result of increasing rates of chronic liver disease, secondary to lifestyle-associated risk factors and the lack of an established screening programme for the general population. Traditionally, radical/curative treatment options for HCC, including liver transplantation and surgical resection are reserved for the minority of patients, presenting with an early stage cancer. For patients with advanced disease, Sorafenib and Lenvatinib were, until recently, the only licensed systemic treatments, and provided only limited survival benefits at the cost of a multitude of potential side effects. Recent scientific advances in the field of cancer immunotherapy have renewed significant interest in advanced HCC, in order to fulfil this apparent area of unmet clinical need. This has led to the success and recent regulatory approval of an Atezolizumab/Bevacizumab combination for the first-line treatment of advanced HCC following results from the IMbrave150 clinical trial in 2019, with further immune checkpoint inhibitors currently undergoing testing in advanced clinical trials. Furthermore, other cancer immunotherapies, including chimeric antigen receptor T-cells, dendritic cell vaccines and oncolytic viruses are also in early stage clinical trials, for the treatment of advanced HCC. This review will summarise the major approaches that have been and are currently in development for the systemic treatment of advanced HCC, their advantages, drawbacks, and predictions of where this revolutionary treatment field will continue to travel for the foreseeable future.

Systematic Investigation of Biocompatible Cationic Polymeric Nucleic Acid Carriers for Immunotherapy of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the third-largest cause of cancer death worldwide, while immunotherapy is rapidly being developed to fight HCC with great potential. Nucleic acid drugs are the most important modulators in HCC immunotherapy. To boost the efficacy of therapeutics and amplify the efficiency of genetic materials, biocompatible polymers are commonly used. However, under the strong need of a summary for current developments of biocompatible polymeric nucleic acid carriers for immunotherapy of HCC, there is rare review article specific to this topic to our best knowledge. In this article, we will discuss the current progress of immunotherapy for HCC, biocompatible cationic polymers (BCPs) as nucleic acid carriers used (or potential) to fight HCC, the roles of biocompatible polymeric carriers for nucleic acid delivery, and nucleic acid delivery by biocompatible polymers for immunotherapy. At the end, we will conclude the review and discuss future perspectives. This article discusses biocompatible polymeric nucleic acid carriers for immunotherapy of HCC from multidiscipline perspectives and provides a new insight in this domain. We believe this review will be interesting to polymer chemists, pharmacists, clinic doctors, and PhD students in related disciplines.

A three-phase trans-ethnic study reveals B7-H3 expression is a significant and independent biomarker associated with colon cancer overall survival

BACKGROUND

There have been inconsistent results and conflicting conclusions among the existing prognostic studies of B7-H3 expression in colon cancer patients. Therefore, the association between B7-H3 expression and colon cancer survival has remained largely unclear.

METHODS

We performed a three-phase and trans-ethnic prognostic study of B7-H3 expression in colon cancer patients involving perhaps the largest population to date. In the discovery phase, we utilized a Cox proportional hazards model adjusted for covariates to test the association between B7-H3 expression and colon cancer overall survival (OS) time in a European population from The Cancer Genome Atlas (TCGA) cohort (n=433). In the validation phase I, the association was replicated in a European population from Gene Expression Omnibus (GEO) cohort (n=811). In the validation phase II, we again confirmed the significant association in an Asian population from Fujian Medical University Union Hospital (UNION) cohort (n=179). Furthermore, a series of Kaplan-Meier analysis, bioinformatics analysis of tumor immune microenvironment (TIME), and immune checkpoint prognostic prediction analysis, as well as sensitivity analysis, were also conducted.

RESULTS

Highly expressed B7-H3 was a significant and robust biomarker to colon cancer survival, with a large hazard ratio (HR) [HRTCGA =4.60, 95% confidence interval (CI): 2.15 to 9.83, P=8.37×10-05; HRGEO =1.47, 95% CI: 1.12 to 1.94, P=0.0056; HRUNION =1.63, 95% CI: 1.36 to 1.95, P=7.91×10-08]. We detected an involvement of B7-H3 in the tumor immune microenvironment (TIME). Meanwhile, B7-H3 was significantly and weakly correlated with 6 out of 27 well-recognized immune checkpoint genes. Even after adjusting for effects of other immune checkpoint genes, B7-H3 still exhibited a harmful effect on colon cancer survival using samples from TCGA and GEO cohorts (HR =1.47, 95% CI: 1.07 to 2.02, P=0.0184), indicating that it was an independent prognostic factor of colon cancer. We also proposed an immune checkpoint prognostic risk score which possessed the capability to identify colon cancers with high risk of mortality.

CONCLUSIONS

The expression of B7-H3 is a significant, robust, and independent prognostic factor to colon cancer OS.

Therapeutic cancer vaccines revamping: technology advancements and pitfalls

Cancer vaccines (CVs) represent a long-sought therapeutic and prophylactic immunotherapy strategy to obtain antigen (Ag)-specific T-cell responses and potentially achieve long-term clinical benefit. However, historically, most CV clinical trials have resulted in disappointing outcomes, despite promising signs of immunogenicity across most formulations. In the past decade, technological advances regarding vaccine delivery platforms, tools for immunogenomic profiling, and Ag/epitope selection have occurred. Consequently, the ability of CVs to induce tumor-specific and, in some cases, remarkable clinical responses have been observed in early-phase clinical trials. It is notable that the record-breaking speed of vaccine development in response to the coronavirus disease-2019 pandemic mainly relied on manufacturing infrastructures and technological platforms already developed for CVs. In turn, research, clinical data, and infrastructures put in place for the severe acute respiratory syndrome coronavirus 2 pandemic can further speed CV development processes. This review outlines the main technological advancements as well as major issues to tackle in the development of CVs. Possible applications for unmet clinical needs will be described, putting into perspective the future of cancer vaccinology.

Interrogation of the microenvironmental landscape in spinal ependymomas reveals dual functions of tumor-associated macrophages

Spinal ependymomas are the most common spinal cord tumors in adults, but their intratumoral cellular heterogeneity has been less studied, and how spinal microglia are involved in tumor progression is still unknown. Here, our single-cell RNA-sequencing analyses of three spinal ependymoma subtypes dissect the microenvironmental landscape of spinal ependymomas and reveal tumor-associated macrophage (TAM) subsets with distinct functional phenotypes. CCL2+ TAMs are related to the immune response and exhibit a high capacity for apoptosis, while CD44+ TAMs are associated with tumor angiogenesis. By combining these results with those of single-cell ATAC-sequencing data analysis, we reveal that TEAD1 and EGR3 play roles in regulating the functional diversity of TAMs. We further identify diverse characteristics of both malignant cells and TAMs that might underlie the different malignant degrees of each subtype. Finally, assessment of cell-cell interactions reveal that stromal cells act as extracellular factors that mediate TAM diversity. Overall, our results reveal dual functions of TAMs in tumor progression, providing valuable insights for TAM-targeting immunotherapy.

STimulator of INterferon Genes Agonism Accelerates Anti-tumor Activity in Poorly Immunogenic Tumors

The innate immune agonist STING (STimulator of INterferon Genes) binds its natural ligand 2'3'-cGAMP (cyclic guanosine-adenosine monophosphate) and initiates type I interferon production. This promotes systemic antigen-specific CD8+ T-cell priming that eventually provides potent anti-tumor activity. To exploit this mechanism, we synthesized a novel STING agonist, MSA-1, that activates both mouse and human STING with higher in vitro potency than cGAMP. Following intratumoral (IT) administration of MSA-1 to a panel of syngeneic mouse tumors on immune-competent mice, cytokine upregulation and its exposure were detected in plasma, other tissues, injected tumors, and noninjected tumors. This was accompanied by effective anti-tumor activity. Mechanistic studies in immune-deficient mice suggested that anti-tumor activity of IT-dosed STING agonists is in part due to necrosis and/or innate immune responses such as tumor necrosis factor α (TNF-α) activity, but development of a robust adaptive anti-tumor immunity is necessary for complete tumor elimination. Combination with PD-1 blockade in anti-PD-1-resistant murine models demonstrated that MSA-1 may synergize with checkpoint inhibitors but can also provide superior tumor control as a single agent. We show for the first time that potent cyclic dinucleotides can promote a rapid and stronger induction of the same genes eventually regulated by PD-1 blockade. This may have contributed to the relatively early tumor control observed with MSA-1. Taken together, these data strongly support the development of STING agonists as therapy for patients with aggressive tumors that are partially responsive or nonresponsive to single-agent anti-PD-1 treatment by enhancing the anti-PD-1 immune profile.

Light-controlled elimination of PD-L1+ cells

The programmed death ligand-1 (PD-L1), also known as CD274 or B7-H1, is mainly expressed on cancer cells and/or immunosuppressive cells in the tumor microenvironment (TME) and plays an essential role in tumor progression and immune escape. Immune checkpoint inhibitors (ICIs) of the PD-1/PD-L1 axis have shown impressive clinical success, however, the majority of the patients do not respond to immune checkpoint therapy (ICT). Thus, to overcome ICT resistance there is a high need for potent and novel strategies that simultaneously target both tumor cells and immunosuppressive cells in the TME. In this study, we show that the intracellular light-controlled drug delivery method photochemical internalization (PCI) induce specific and strongly enhanced cytotoxic effects of the PD-L1-targeting immunotoxin, anti-PD-L1-saporin (Anti-PDL1-SAP), in the PD-L1+ triple-negative breast cancer MDA-MB-231 cell line, while no enhanced efficacy was obtained in the PD-L1 negative control cell line MDA-MB-453. Using fluorescence microscopy, we reveal that the anti-PD-L1 antibody binds to PD-L1 on the surface of the MDA-MD-231 cells and overnight accumulates in late endosomes and lysosomes where it co-localizes with the PCI photosensitizer fimaporfin (TPCS_2a). Moreover, light-controlled endosomal/lysosomal escape of the anti-PD-L1 antibody and fimaporfin into the cytosol was obtained. We also confirm that the breast MDA-MB-468 and the prostate PC-3 and DU-145 cancer cell lines have subpopulations with PD-L1 expression. In addition, we show that interferon-gamma strongly induce PD-L1 expression in the per se PD-L1 negative CT26.WT cells and enhance the PD-L1 expression in MC-38 cells, of which both are murine colon cancer cell lines. In conclusion, our work provides an in vitro proof-of-concept of PCI-enhanced targeting and eradication of PD-L1 positive immunosuppressive cells. This light-controlled combinatorial strategy has a potential to advance cancer immunotherapy and should be explored in preclinical studies.

Radiation combines with immune checkpoint blockade to enhance T cell priming in a murine model of poorly immunogenic pancreatic cancer

Radiation has been a pillar of cancer therapy for decades. The effects of radiation on the anti-tumour immune response are variable across studies and have not been explicitly defined in poorly immunogenic tumour types. Here, we employed combination checkpoint blockade immunotherapy with stereotactic body radiation therapy and examined the effect on tumour growth and immune infiltrates in subcutaneous and orthotopic mouse models of pancreatic cancer. Although immune checkpoint blockade and radiation were ineffective alone, their combination produced a modest growth delay in both irradiated and non-irradiated tumours that corresponded with significant increases in CD8+ T cells, CD4+ T cells and tumour-specific T cells as identified by IFNγ ELISpot. We conclude that radiation enhances priming of tumour-specific T cells in poorly immunogenic tumours and that the frequency of these T cells can be further increased by combination with immune checkpoint blockade.

Inhibition of CDK4/6 Promotes CD8 T-cell Memory Formation

CDK4/6 inhibitors are approved to treat breast cancer and are in trials for other malignancies. We examined CDK4/6 inhibition in mouse and human CD8+ T cells during early stages of activation. Mice receiving tumor-specific CD8+ T cells treated with CDK4/6 inhibitors displayed increased T-cell persistence and immunologic memory. CDK4/6 inhibition upregulated MXD4, a negative regulator of MYC, in both mouse and human CD8+ T cells. Silencing of Mxd4 or Myc in mouse CD8+ T cells demonstrated the importance of this axis for memory formation. We used single-cell transcriptional profiling and T-cell receptor clonotype tracking to evaluate recently activated human CD8+ T cells in patients with breast cancer before and during treatment with either palbociclib or abemaciclib. CDK4/6 inhibitor therapy in humans increases the frequency of CD8+ memory precursors and downregulates their expression of MYC target genes, suggesting that CDK4/6 inhibitors in patients with cancer may augment long-term protective immunity. SIGNIFICANCE: CDK4/6 inhibition skews newly activated CD8+ T cells toward a memory phenotype in mice and humans with breast cancer. CDK4/6 inhibitors may have broad utility outside breast cancer, particularly in the neoadjuvant setting to augment CD8+ T-cell priming to tumor antigens prior to dosing with checkpoint blockade.This article is highlighted in the In This Issue feature, p. 2355.