Induced expression of PD-1, a novel member of the immunoglobulin gene superfamily, upon programmed cell death

Multifaceted roles of PD-1 in tumorigenesis: From immune checkpoint to tumor cell-intrinsic function

Programmed cell death 1 (PD-1), a key immune checkpoint receptor, has been extensively studied for its role in regulating immune responses in cancer. However, recent research has unveiled a complex and dual role for PD-1 in tumorigenesis. While PD-1 is traditionally associated with immune cells, this article explores its expression in various cancer cells and its impact on cancer progression. PD-1's functions extend beyond immune regulation, as it has been found to both promote and suppress tumor growth, depending on the cancer type. These findings have significant implications for the future of cancer treatment and our understanding of the immune response in the context of cancer. This article calls for further research into the multifaceted roles of PD-1 to optimize its therapeutic potential and improve patient outcomes in the fight against cancer.

VISTA: A Novel Checkpoint for Cancer Immunotherapy

V-domain Ig suppressor of T cell activation (VISTA) is a recently identified member of the B7 family of immunoregulatory proteins. It is pivotal for maintaining T cell quiescence and exerts a significant regulatory influence on the immune response to tumors. Accumulating clinical evidence suggests that the influence of VISTA on tumor immunity is more nuanced than initially postulated. Although these revelations add layers of complexity to our understanding of the function of VISTA, they also offer novel avenues for scientific inquiry and potential therapeutic targets. In this review, we scrutinize the current literature pertaining to the expression of VISTA in various of malignancies, aiming to elucidate its intricate roles within the tumor microenvironment and in cancer immunotherapy.

Aptamer-assisted phage display: enhancing checkpoint inhibition with a peptide and an aptamer targeting distinct sites on a single PD-L1 protein

Utilizing a novel approach known as aptamer-assisted phage display (APD), we identified an anti-PD-L1 peptide, NV Pep, capable of simultaneous binding to PD-L1 alongside the DNA aptamer MJ5C. Combined inhibition using NV Pep and MJ5C demonstrated significant enhancement compared to individual ligands against the PD-1/PD-L1 interaction.

Design, Synthesis, and Biological Evaluation of Chroman Derivatives as PD-1/PD-L1 Antagonists

Programmed death-ligand 1 (PD-L1) has emerged as a promising therapeutic target for various cancers due to its crucial role in promoting tumor immune evasion. Here, we report a novel class of chroman-like small-molecule PD-L1 inhibitors exhibiting significant activity in inhibiting the PD-1/PD-L1 interaction. Employing a "ring-close" strategy for conformational restriction, we have achieved compound C27, which demonstrates superior PD-1/PD-L1 inhibitory activity compared to the positive control. Molecular dynamics simulation and binding free energy calculation predict that (R)-C27 with inhibitory activity surpassed (S)-C27. The experimental results from bioassay and X-ray structural analysis corroborate these findings. All these results collectively indicate that (R)-C27 is a promising lead compound deserving further exploration.

Advances in immunotherapy for breast cancer and feline mammary carcinoma: From molecular basis to novel therapeutic targets

The role of inflammation in cancer is a topic that has been investigated for many years. As established, inflammation emerges as a defining characteristic of cancer, presenting itself as a compelling target for therapeutic interventions in the realm of oncology. Controlling the tumor microenvironment (TME) has gained paramount significance, modifying not only the effectiveness of immunotherapy but also modulating the outcomes and prognoses of standard chemotherapy and other anticancer treatments. Immunotherapy has surfaced as a central focus within the domain of tumor treatments, using immune checkpoint inhibitors as cancer therapy. Immune checkpoints and their influence on the tumor microenvironment dynamic are presently under investigation, aiming to ascertain their viability as therapeutic interventions across several cancer types. Cancer presents a significant challenge in humans and cats, where female breast cancer ranks as the most prevalent malignancy and feline mammary carcinoma stands as the third most frequent. This review seeks to summarize the data about the immune checkpoints cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4), lymphocyte activation gene-3 (LAG-3), programmed cell death protein-1 (PD-1), V-domain Ig suppressor of T cell activation (VISTA), and T-cell immunoglobulin and mucin domain 3 (TIM-3) respective ongoing investigations as prospective targets for therapy for human breast cancer, while also outlining findings from studies reported on feline mammary carcinoma (FMC), strengthening the rationale for employing FMC as a representative model in the exploration of human breast cancer.

Enzymatic depletion of circulating glutamine is immunosuppressive in cancers

Although glutamine addiction in cancer cells is extensively reported, there is controversy on the impact of glutamine metabolism on the immune cells within the tumor microenvironment (TME). To address the role of extracellular glutamine, we enzymatically depleted circulating glutamine using PEGylated Helicobacter pylori gamma-glutamyl transferase (PEG-GGT) in syngeneic mouse models of breast and colon cancers. PEG-GGT treatment inhibits growth of cancer cells in vitro, but in vivo it increases myeloid-derived suppressor cells (MDSCs) and has no significant impact on tumor growth. By deriving a glutamine depletion signature, we analyze diverse human cancers within the TCGA and illustrate that glutamine depletion is not associated with favorable clinical outcomes and correlates with accumulation of MDSC. Broadly, our results help clarify the integrated impact of glutamine depletion within the TME and advance PEG-GGT as an enzymatic tool for the systemic and selective depletion (no asparaginase activity) of circulating glutamine in live animals.

Programmed Cell Death Ligand 1 (PD-L1) Immunohistochemical Expression in Advanced Urothelial Bladder Carcinoma: An Updated Review with Clinical and Pathological Implications

The management of advanced bladder carcinoma involves a multidisciplinary approach, but the prognosis remains poor for many patients. The immune system plays a crucial role in this disease, influencing both tumor development and response to treatment, and exploiting the immune system against the tumor can be a valuable strategy to destroy neoplastic cells. This is the biological principle underlying Bacillus Calmette-Guérin (BCG) use and, more recently, immune checkpoint inhibitors (ICIs), like PD-1 (programmed death-1)/PD-L1 (programmed death-ligand 1) inhibitors. In fact, one of the best studied immune checkpoints is represented by the PD-1/PD-L1 axis, which is a well-known immune escape system adopted by neoplastic bladder cells. PD-L1 expression has been associated with a higher pathologic stage and has shown prognostic value in bladder carcinoma. Interestingly, high-grade bladder cancers tend to express higher levels of PD-1 and PD-L1, suggesting a potential role of such an axis in mediating disease progression. Immunotherapy with PD-1 and PD-L1 inhibitors has therefore emerged as a valuable treatment option and has shown efficacy in advanced bladder cancer patients, with high PD-L1 expression levels associated with better treatment responses. Our review aims to provide a comprehensive overview of the role of PD-L1 in advanced bladder cancer, focusing on its implications for treatment decisions and the prediction of treatment response. Overall, our work aims to contribute to the understanding of PD-L1 as a predictive biomarker and highlight its role in shaping therapeutic approaches for advanced bladder cancer.

Subtype-specific alternative splicing events in breast cancer identified by large-scale data analysis

Genome analysis in cancer has focused mainly on elucidating the function and regulatory mechanisms of genes that exhibit differential expression or mutation in cancer samples compared to normal samples. Recently, transcriptome analysis revealed that abnormal splicing events in cancer samples could contribute to cancer pathogenesis. Moreover, splicing variants in cancer reportedly generate diverse cancer antigens. Although abnormal splicing events are expected to be potential targets in cancer immunotherapy, the exploration of such targets and their biological significance in cancer have not been fully understood. In this study, to explore subtype-specific alternative splicing events, we conducted a comprehensive analysis of splicing events for each breast cancer subtype using large-scale splicing data derived from The Cancer Genome Atlas and found subtype-specific alternative splicing patterns. Analyses indicated that genes that produce subtype-specific alternative splicing events are potential novel targets for immunotherapy against breast cancer. The subtype-specific alternative splicing events identified in this study, which were not identified by mutation or differential expression analysis, bring new significance to previously overlooked splicing events.

Association between specific human leukocyte antigen alleles and development of thyroid immune-related adverse event

Aim: Inherent variations in human leukocyte antigen (HLA) alleles have been revealed epidemiologically to influence the development of autoimmune diseases. HLA alleles may thus also be associated with the development of immune-related adverse events (irAEs), such as thyroid irAE. Materials & methods: In this case-control study, 71 cancer patients who received immune checkpoint inhibitors were enrolled and HLA-genotyped and the frequency of HLA alleles was compared. Results: A*26:01, DPA1*01:03 and DPB1*02:01 were significantly more frequent in patients with thyroid irAE than in patients without any irAEs (35.0 vs 3.2% [p = 0.004], 80.0 vs 45.2% [p = 0.020] and 55.0 vs 25.8% [p = 0.044], respectively). Conclusion: A*26:01, DPA1*01:03 and DPB1*02:01 appear to be associated with thyroid irAE.

The rapidly changing field of predictive biomarkers of non-small cell lung cancer

Lung cancer is a leading cause of cancer-related death worldwide in both men and women, however mortality in the US and EU are recently declining in parallel with the gradual cut of smoking prevalence. Consequently, the relative frequency of adenocarcinoma increased while that of squamous and small cell carcinomas declined. During the last two decades a plethora of targeted drug therapies have appeared for the treatment of metastasizing non-small cell lung carcinomas (NSCLC). Personalized oncology aims to precisely match patients to treatments with the highest potential of success. Extensive research is done to introduce biomarkers which can predict the effectiveness of a specific targeted therapeutic approach. The EGFR signaling pathway includes several sufficient targets for the treatment of human cancers including NSCLC. Lung adenocarcinoma may harbor both activating and resistance mutations of the EGFR gene, and further, mutations of KRAS and BRAF oncogenes. Less frequent but targetable genetic alterations include ALK, ROS1, RET gene rearrangements, and various alterations of MET proto-oncogene. In addition, the importance of anti-tumor immunity and of tumor microenvironment has become evident recently. Accumulation of mutations generally trigger tumor specific immune defense, but immune protection may be upregulated as an aggressive feature. The blockade of immune checkpoints results in potential reactivation of tumor cell killing and induces significant tumor regression in various tumor types, such as lung carcinoma. Therapeutic responses to anti PD1-PD-L1 treatment may correlate with the expression of PD-L1 by tumor cells. Due to the wide range of diagnostic and predictive features in lung cancer a plenty of tests are required from a single small biopsy or cytology specimen, which is challenged by major issues of sample quantity and quality. Thus, the efficacy of biomarker testing should be warranted by standardized policy and optimal material usage. In this review we aim to discuss major targeted therapy-related biomarkers in NSCLC and testing possibilities comprehensively.

Cancer treatments: Past, present, and future

There is a rich history of cancer treatments which provides a number of important lessons for present and future cancer therapies. We outline this history by looking in the past, reviewing the current landscape of cancer treatments, and by glancing at the potential future cancer therapies.

Advances of ultrasound in tumor immunotherapy

Immunotherapy has become a revolutionary method for treating tumors, offering new hope to cancer patients worldwide. Immunotherapy strategies such as checkpoint inhibitors, chimeric antigen receptor T-cell (CAR-T) therapy, and cancer vaccines have shown significant potential in clinical trials. Despite the promising results, there are still limitations that impede the overall effectiveness of immunotherapy; the response to immunotherapy is uneven, the response rate of patients is still low, and systemic immune toxicity accompanied with tumor cell immune evasion is common. Ultrasound technology has evolved rapidly in recent years and has become a significant player in tumor immunotherapy. The introductions of high intensity focused ultrasound and ultrasound-stimulated microbubbles have opened doors for new therapeutic strategies in the fight against tumor. This paper explores the revolutionary advancements of ultrasound combined with immunotherapy in this particular field.

Beyond Anti-PD-1/PD-L1: Improving Immune Checkpoint Inhibitor Responses in Triple-Negative Breast Cancer

The introduction of anti-programmed cell death protein-1 (anti-PD-1) to the clinical management of triple-negative breast cancer (TNBC) represents a breakthrough for a disease whose treatment has long relied on the standards of chemotherapy and surgery. Nevertheless, few TNBC patients achieve a durable remission in response to anti-PD-1, and there is a need to develop strategies to maximize the potential benefit of immune checkpoint inhibition (ICI) for TNBC patients. In the present review, we discuss three conceptual strategies to improve ICI response rates in TNBC patients. The first effort involves improving patient selection. We discuss proposed biomarkers of response and resistance to anti-PD-1, concluding that an optimal biomarker will likely be multifaceted. The second effort involves identifying existing targeted therapies or chemotherapies that may synergize with ICI. In particular, we describe recent efforts to use inhibitors of the PI3K/AKT or RAS/MAPK/ERK pathways in combination with ICI. Third, considering the possibility that targeting the PD-1 axis is not the most promising strategy for TNBC treatment, we describe ongoing efforts to identify novel immunotherapy strategies.

Navigating the landscape of PD-1/PD-L1 imaging tracers: from challenges to opportunities

Immunotherapy targeted to immune checkpoint inhibitors, such as the program cell death receptor (PD-1) and its ligand (PD-L1), has revolutionized cancer treatment. However, it is now well-known that PD-1/PD-L1 immunotherapy response is inconsistent among patients. The current challenge is to customize treatment regimens per patient, which could be possible if the PD-1/PD-L1 expression and dynamic landscape are known. With positron emission tomography (PET) imaging, it is possible to image these immune targets non-invasively and system-wide during therapy. A successful PET imaging tracer should meet specific criteria concerning target affinity, specificity, clearance rate and target-specific uptake, to name a few. The structural profile of such a tracer will define its properties and can be used to optimize tracers in development and design new ones. Currently, a range of PD-1/PD-L1-targeting PET tracers are available from different molecular categories that have shown impressive preclinical and clinical results, each with its own advantages and disadvantages. This review will provide an overview of current PET tracers targeting the PD-1/PD-L1 axis. Antibody, peptide, and antibody fragment tracers will be discussed with respect to their molecular characteristics and binding properties and ways to optimize them.

Endocrine adverse events in patients with cancer receiving perioperative immune checkpoint blockade: a meta-analysis of randomized controlled trials

Background

Perioperative use of immune checkpoint blockade (ICB) improves survival in patients with early-stage cancer. Treatment-related adverse events (AEs), frequently involve the endocrine system which may increase perioperative complications and affect quality of life.

Objective

We conducted a meta-analysis to elucidate the impact of adding ICB to conventional neoadjuvant/adjuvant therapy on the incidence of endocrine AEs.

Design

A systematic review and meta-analysis of randomize-controlled trials (RCTs).

Data sources and methods

A systematic search of PubMed, Embase, Web of Science, and Cochrane library was performed for RCTs comparing groups with and without the addition of ICB to conventional perioperative therapy in patients with cancer. Outcomes included all-grade and grade 3-5 thyroiditis, hyperthyroidism, hypothyroidism, adrenal insufficiency, hypophysitis, type 1 diabetes mellitus, and hyperglycemia. The odds ratios (ORs) of all-grade and grade 3-5 endocrine were pooled using the random-effect model meta-analysis.

Results

Twenty-four RCTs comprising 12,199 patients were identified for meta-analysis. The addition of ICB was associated with higher incidence of thyroiditis [all grade: OR = 3.53 (95% confidence interval (CI): 1.88-6.64)], hyperthyroidism [all-grade: 7.18 (4.30-12.01); grade 3-5: 3.93 (1.21-12.82)], hypothyroidism [all-grade: 5.39 (3.68-7.90); grade 3-5: 3.63 (1.18-11.11)], adrenal insufficiency [all-grade: 3.82 (1.88-7.79); grade 3-5: 5.91 (2.36-14.82)], hypophysitis [all-grade: 10.29 (4.97-21.3); grade 3-5: 5.80 (1.99-16.92)], and type 1 diabetes mellitus [all-grade: 2.24 (1.06-4.74); grade 3-5: 3.49 (1.21-10.08)]. The cumulative incidence of each grade 3-5 endocrine AE was low (<1.3%). No grade 5 AEs leading to death were observed.

Conclusion

The addition of neoadjuvant/adjuvant ICB to conventional therapy was associated with an increased incidence of several endocrine AEs. Clinicians should be aware of the risk of endocrinopathy from the perioperative ICB use to facilitate risk-benefit discussion with patients with early-stage cancer.

Trial registration

The protocol of this research was registered in PROSPERO (CRD42022332624).

C2-Symmetrical Terphenyl Derivatives as Small Molecule Inhibitors of Programmed Cell Death 1/Programmed Death Ligand 1 Protein-Protein Interaction

The PD-1/PD-L1 complex is an immune checkpoint responsible for regulating the natural immune response, but also allows tumors to escape immune surveillance. Inhibition of the PD-1/PD-L1 axis positively contributes to the efficacy of cancer treatment. The only available therapeutics targeting PD-1/PD-L1 are monoclonal antibody-based drugs, which have several limitations. Therefore, small molecule compounds are emerging as an attractive alternative that can potentially overcome the drawbacks of mAb-based therapy. In this article, we present a novel class of small molecule compounds based on the terphenyl scaffold that bind to PD-L1. The general architecture of the presented structures is characterized by axial symmetry and consists of three elements: an m-terphenyl core, an additional aromatic ring, and a solubilizing agent. Using molecular docking, we designed a series of final compounds, which were subsequently synthesized and tested in HTRF assay and NMR binding assay to evaluate their activity. In addition, we performed an in-depth analysis of the mutual arrangement of the phenyl rings of the terphenyl core within the binding pocket of PD-L1 and found several correlations between the plane angle values and the affinity of the compounds towards the protein.

Anti-PD-L1 antibodies promote cellular proliferation by activating the PD-L1-AXL signal relay in liver cancer cells

BACKGROUND

Immune checkpoint inhibitors (ICIs) are emerging treatments for advanced hepatocellular carcinoma (HCC); however, evidence has shown they may induce hyperprogressive disease via unexplained mechanisms.

METHODS

In this study, we investigated the possible stimulative effect of ICIs on programmed cell death-ligand 1 (PD-L1)-harboring liver cancer cells under immunocompetent cell-free conditions.

RESULTS

The sarcomatous HAK-5 cell line displayed the highest expression of PD-L1 among 11 human liver cancer cell lines used in this study. HLF showed moderate expression, while HepG2, Hep3B, and HuH-7 did not show any. Moreover, sarcomatous HCC tissues expressed high levels of PD-L1. We observed approximately 20% increase in cell proliferation in HAK-5 cells treated with anti-PD-L1 antibodies, such as durvalumab and atezolizumab, for 48 h compared with that of those treated with the control IgG and the anti-PD-1 antibody pembrolizumab. No response to durvalumab or atezolizumab was shown in PD-L1-nonexpressing cells. Loss-of-function and gain-of-function experiments for PD-L1 in HAK-5 and HepG2 cells resulted in a significant decrease and increase in cell proliferation, respectively. Phosphorylated receptor tyrosine kinase array and immunoprecipitation revealed direct interactions between PD-L1 and AXL in tumor cells. This was stabilized by extrinsic anti-PD-L1 antibodies in a glycosylated PD-L1-dependent manner. Activation of AXL, triggering signal relay to the Akt and Erk pathways, boosted tumor cell proliferation both in vitro and in xenografted tumors in NOD/SCID mice.

CONCLUSION

Collectively, this suggests that anti-PD-L1 antibodies stimulate cell proliferation via stabilization of the PD-L1-AXL complex in specific types of liver cancer, including in HCC with mesenchymal components.

SIGNIFICANCE

Therapeutic anti-PD-L1 antibodies promote cell proliferation by stabilizing the PD-L1-AXL complex in PD-L1-abundant neoplasms, including in HCC with mesenchymal components. Such a mechanism may contribute to the development of hyperprogressive disease.

Advances in Immunotherapy in Esophagogastric Cancer

Immune checkpoint inhibitors are rapidly transforming the care of patients with esophagogastric cancer. Particularly, anti-PD-1 therapy has demonstrated promising efficacy in metastatic and resectable disease. In this review, the authors discuss landmark clinical trials, highlight challenges and opportunities in this field, and propose potential directions for future work.

Immune checkpoint molecules in solid organ transplantation: A promising way to prevent rejection

Immune checkpoint (IC) molecules modulate immune responses upon antigen presentation; the interaction between different IC molecules will result in the stimulation or, rather, the thwarting of such responses. Tumor cells express increased amounts of inhibitory IC molecules in an attempt to evade immune responses; therapeutic agents have been developed that bind inhibitory IC molecules, restoring tumor-directed immune responses and changing the prognosis of a number of cancers. Stimulation of inhibitory IC molecules could be beneficial in preventing rejection in the setting of solid organ transplantation (SOT), and in vivo as well as in vivo results obtained in animal models show this to indeed to be the case. With the exception of belatacept, a monoclonal antibody (mAb) in which an IgG Fc fragment is linked to the extracellular domain of CTLA-4, this has not yet translated into the generation of novel therapeutic approaches to prevent SOT rejection. We provide a review of state-of-the art knowledge on the role played by IC molecules in transplantation, confident that innovative research will lead to new avenues to manage rejection in solid organ transplant.

Unveiling the promise of PD1/PD-L1: A new dawn in immunotherapy for cholangiocarcinoma

Cholangiocarcinoma (CCA), a rare yet notably aggressive cancer, has experienced a surge in incidence in recent years. Presently, surgical resection remains the most effective curative strategy for CCA. Nevertheless, a majority of patients with CCA are ineligible for surgical removal at the time of diagnosis. For advanced stages of CCA, the combination of gemcitabine and cisplatin is established as the standard chemotherapy regimen. Despite this, treatment efficacy is often hindered by the development of resistance. In recent times, immune checkpoint inhibitors, particularly those that block programmed death 1 and its ligand (PD1/PD-L1), have emerged as promising strategies against a variety of cancers and are being increasingly integrated into the therapeutic landscape of CCA. A growing body of research supports that the use of PD1/PD-L1 monoclonal antibodies in conjunction with chemotherapy may significantly improve patient outcomes. This article seeks to meticulously review the latest studies on PD1/PD-L1 involvement in CCA, delving into their expression profiles, prognostic significance, contribution to oncogenic processes, and their potential clinical utility.

Advancing cancer immunotherapy through siRNA-based gene silencing for immune checkpoint blockade

Cancer immunotherapy represents a revolutionary strategy, leveraging the patient's immune system to inhibit tumor growth and alleviate the immunosuppressive effects of the tumor microenvironment (TME). The recent emergence of immune checkpoint blockade (ICB) therapies, particularly following the first approval of cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) inhibitors like ipilimumab, has led to significant growth in cancer immunotherapy. The extensive explorations on diverse immune checkpoint antibodies have broadened the therapeutic scope for various malignancies. However, the clinical response to these antibody-based ICB therapies remains limited, with less than 15% responsiveness and notable adverse effects in some patients. This review introduces the emerging strategies to overcome current limitations of antibody-based ICB therapies, mainly focusing on the development of small interfering ribonucleic acid (siRNA)-based ICB therapies and innovative delivery systems. We firstly highlight the diverse target immune checkpoint genes for siRNA-based ICB therapies, incorporating silencing of multiple genes to boost anti-tumor immune responses. Subsequently, we discuss improvements in siRNA delivery systems, enhanced by various nanocarriers, aimed at overcoming siRNA's clinical challenges such as vulnerability to enzymatic degradation, inadequate pharmacokinetics, and possible unintended target interactions. Additionally, the review presents various combination therapies that integrate chemotherapy, phototherapy, stimulatory checkpoints, ICB antibodies, and cancer vaccines. The important point is that when used in combination with siRNA-based ICB therapy, the synergistic effect of traditional therapies is strengthened, improving host immune surveillance and therapeutic outcomes. Conclusively, we discuss the insights into innovative and effective cancer immunotherapeutic strategies based on RNA interference (RNAi) technology utilizing siRNA and nanocarriers as a novel approach in ICB cancer immunotherapy.

Nanomedicine Tumor Targeting

Nanomedicines are extensively explored for cancer therapy. By delivering drug molecules more efficiently to pathological sites and by attenuating their accumulation in healthy organs and tissues, nanomedicine formulations aim to improve the balance between drug efficacy and toxicity. More than 20 cancer nanomedicines are approved for clinical use, and hundreds of formulations are in (pre)clinical development. Over the years, several key pitfalls have been identified as bottlenecks in nanomedicine tumor targeting and translation. These go beyond materials- and production-related issues, and particularly also encompass biological barriers and pathophysiological heterogeneity. In this manuscript, the author describes the most important principles, progress, and products in nanomedicine tumor targeting, delineates key current problems and challenges, and discusses the most promising future prospects to create clinical impact.

Antibody-Mediated Depletion of Autoreactive T Lymphocytes through PD-1 Improves Disease Outcomes and Visualizes T Cell Activation in Experimental Autoimmune Encephalomyelitis

Long-term therapeutic outcomes of multiple sclerosis (MS) remain hindered by the chronic nature of immune cell stimulation toward self-antigens. Development of novel methods to target and deplete autoreactive T lymphocytes remains an attractive target for therapeutics for MS. We developed a programmed cell death 1 (PD-1)-targeted radiolabeled mAb and assessed its ability to deplete activated PD-1+ T lymphocytes in vitro and its ability to reduce disease burden of the myelin oligodendrocyte glycoprotein 35-55 experimental autoimmune encephalomyelitis (EAE) model in C57BL/6 mice. We also investigated the upregulation of PD-1 on infiltrating lymphocytes in an animal model of MS. Finally, we demonstrate the (to our knowledge) first reported positron-emission tomography/computed tomography imaging of activated PD-1+ cells in the EAE animal model of MS. We found that the 177Lu radioisotope-labeled anti-PD-1 mAb demonstrated significant in vitro cytotoxicity toward activated CD4+PD-1+ T lymphocytes and led to significant reduction in overall disease progression in the EAE animal model. Our results show high expression of PD-1 on infiltrating lymphocytes in the spinal cords of EAE diseased animals. Positron-emission tomography/computed tomography imaging of the anti-PD-1 mAb demonstrated significant uptake in the cervical draining lymph nodes highlighting accumulation of activated lymphocytes. Targeted depletion of T lymphocytes using T cell activation markers such as PD-1 may present a novel method to reduce autoimmune attack and inflammation in autoimmune diseases such as MS. Development of multimodal nuclear theranostic agents may present the opportunity to monitor T cell activation via imaging radioisotopes and simultaneously treat MS using therapeutic radioisotopes.

Doxorubicin induces deglycosylation of cancer cell-intrinsic PD-1 by NGLY1

Tumor cells can express the immune checkpoint protein programmed death-1 (PD-1), but how cancer cell-intrinsic PD-1 is regulated in response to cellular stresses remains largely unknown. Here, we uncover a unique mechanism by which the chemotherapy drug doxorubicin (Dox) regulates cancer cell-intrinsic PD-1. Dox upregulates PD-1 mRNA while reducing PD-1 protein levels in tumor cells. Although Dox shortens the PD-1 half-life, it fails to directly induce PD-1 degradation. Instead, we observe that Dox promotes the interaction between peptide-N(4)-(N-acetyl-beta-glucosaminyl)asparagine amidase (NGLY1) and PD-1, facilitating NGLY1-mediated PD-1 deglycosylation and destabilization. The maintenance of PD-1 sensitizes tumor cells to Dox-mediated antiproliferative effects. Our study unveils a regulatory mechanism of PD-1 in response to Dox and highlights a potential role of cancer cell-intrinsic PD-1 in Dox-mediated antitumor effects.

Cellular Alterations in Immune Checkpoint Inhibitor Therapy-Related Cardiac Dysfunction

PURPOSE OF REVIEW

Immune checkpoint inhibitor (ICI) therapy has emerged as a pivotal advancement in cancer treatment, but the widespread adoption has given rise to a growing number of reports detailing significant cardiovascular toxicity. This review concentrates on elucidating the mechanisms behind ICI-related cardiovascular complications, emphasizing preclinical and mechanistic data.

RECENT FINDINGS

Accumulating evidence indicates a more significant role of immune checkpoints in maintaining cardiac integrity than previously understood, and new key scientific data are available to improve our understanding of ICI-related cardiovascular toxicity, including hidden cardiotoxicity. New avenues for innovative concepts are hypothesized, and opportunities to leverage the knowledge from ICI-therapy for pioneering approaches in related scientific domains can be derived from the latest scientific projects. Cardiotoxicity from ICI therapy is a paramount challenge for cardio-oncology. Understanding the underlying effects builds the foundation for tailored cardioprotective approaches in the growing collective at risk for severe cardiovascular complications.

Clinical outcomes and prognostic factors of concurrent chemoradiotherapy for anal squamous cell carcinoma in Japan

BACKGROUND

Concurrent chemoradiotherapy (CCRT) is the standard treatment for locoregional anal squamous cell carcinoma (ASCC) in western countries. However, there have been few reports on the clinical outcomes of CCRT in Japan. This study aimed to evaluate the clinical outcomes of CCRT, prognostic factors, and the clinical impact of programmed cell death-ligand 1 (PD-L1) expression of ASCC in Japan.

METHODS

Patients with locoregional ASCC were enrolled between 2007 and 2017. All patients received CCRT consisting of ≥ 45 Gy of radiation, 5-fluorouracil, and mitomycin C. Disease-free survival (DFS), overall survival (OS), and adverse events (AEs) were estimated. Expression of p16 and PD-L1 were assessed by immunohistochemical staining (IHC).

RESULTS

This study included 36 patients, of whom 30 (83.3%) were female. Among the participants, 32 (88.9%) achieved complete clinical remission, while six (16.7%) experienced recurrence. The five-year DFS and five-year OS were 72.2% and 84.7%, respectively. Grades ≥ 3 serious AEs included neutropenia in 10 (27.7%) and perianal dermatitis in eight (22.2%). In a univariate analysis, male sex, lymph node metastasis, and large tumor size were significantly associated with worse outcome. In a multivariate analysis, tumor size was an independent factor associated with short DFS. Of the 30 patients whose biopsy specimens were available for IHC, 29 (96.7%) were positive for p16, and 13 (43.3%) were positive for PD-L1. However, PD-L1 expression did not show any clinical impact.

CONCLUSIONS

The comparative etiology, clinical outcomes, and prognostic factors of CCRT observed in Japanese patients with locoregional ASCC were consistent with western data.

Analysis of Oral and Gut Microbiome Composition and Its Impact in Patients with Oral Squamous Cell Carcinoma

The impact of gut and oral microbiota on the clinical outcomes of patients with oral squamous cell carcinoma (OSCC) is unknown. We compared the bacterial composition of dental plaque and feces between patients with OSCC and healthy controls (HCs). Fecal and dental plaque samples were collected from 7 HCs and 18 patients with OSCC before treatment initiation. Terminal restriction fragment-length polymorphism analysis of 16S rRNA genes was performed. Differences in bacterial diversity between the HC and OSCC groups were examined. We compared the occupancy of each bacterial species in samples taken from patients with OSCC and HCs and analyzed the correlation between PD-L1 expression in the tumor specimens and the occupancy of each bacterial species. The gut and oral microbiota of patients with OSCC were more varied than those of HCs. Porphyromonas and Prevotella were significantly more abundant in patients with OSCC than in HCs. The abundance of Clostridium subcluster XIVa in the gut microbiota of the PD-L1-positive group was significantly greater than that in the PD-L1-negative group. The oral and gut microbiomes of patients with OSCC were in a state of dysbiosis. Our results suggest the possibility of new cancer therapies targeting these disease-specific microbiomes using probiotics and synbiotics.

PD-L1 blockade in mitigating severe acute pancreatitis induced pancreatic damage through modulation of immune cell apoptosis

Acute pancreatitis (AP) is a prevalent gastrointestinal disorder. The immune response plays a crucial role in AP progression. However, the impact of immune regulatory checkpoint PD-L1 on severe acute pancreatitis (SAP) remains uncertain. Hence, this study aimed to examine the influence of PD-L1 on SAP. We assessed PD-L1 expression in neutrophils and monocytes obtained from SAP patients. We induced SAP in C57BL/6J mice, PD-L1 gene-deficient mice, and PD-L1 humanized mice using intraperitoneal injections of cerulein plus lipopolysaccharide. Prior to the initial cerulein injection, a PD-L1 inhibitor was administered. Pancreatic tissues were collected for morphological and immunohistochemical evaluation, and serum levels of amylase, lipase, and cytokines were measured. Flow cytometry analysis was performed using peripheral blood cells. The expression of PD-L1 in neutrophils and monocytes was significantly higher in SAP patients compared to healthy individuals. Likewise, the expression of PD-L1 in inflammatory cells in the peripheral blood of SAP-induced C57BL/6J mice was notably higher than in the control group. In mice with PD-L1 deficiency, SAP model exhibited lower pancreatic pathology scores, amylase, lipase, and cytokine levels compared to wild-type mice. PD-L1 deletion resulted in reduced neutrophil apoptosis, leading to an earlier peak in neutrophil apoptosis. Furthermore, it decreased early monocyte apoptosis and diminished the peak of T lymphocyte apoptosis. Within the SAP model, administration of a PD-L1 inhibitor reduced pancreatic pathology scores, amylase, lipase, and cytokine levels in both C57BL/6J mice and PD-L1 humanized mice. These findings suggest that inhibiting PD-L1 expression can alleviate the severity of SAP.

Accelerating Cellular Uptake with Unnatural Amino Acid for Inhibiting Immunosuppressive Cancer Cells

Targeting immunosuppressive metastatic cancer cells is a key challenge in therapy. We recently have shown that a rigid-rod aromatic, pBP-NBD, that responds to enzymes and kill immunosuppressive metastatic osteosarcoma (mOS) and castration resistant prostate cancer (CRPC) cells in mimetic bone microenvironment. However, pBP-NBD demonstrated moderate efficacy against CRPC cells. To enhance activity, we incorporated the unnatural amino acid L- or D-4,4'-biphenylalanine (L- or D-BiP) into pBP-NBD, drastically increasing cellular uptake and CRPC inhibition. Specifically, we inserted BiP into pBP-NBD to target mOS (Saos2 and SJSA1) and CRPC (VCaP and PC3) cells with overexpressed phosphatases. Our results show that the D-peptide backbone with an aspartate methyl diester at the C-terminal offers the highest activity against these immunosuppressive mOS and CRPC cells. Importantly, imaging shows that the peptide assemblies almost instantly enter the cells and accumulate primarily within the endoplasmic reticulum of Saos2, SJSA1, and PC3 cells and at the lysosomes of VCaP cells. By using BiP to boost cellular uptake and self-assembly within cancer cells, this work illustrates an unnatural hydrophobic amino acid as a versatile and effective residue to boost endocytosis of synthetic peptides for intracellular self-assembly.

A new perspective on hematological malignancies: m6A modification in immune microenvironment

Immunotherapy for hematological malignancies is a rapidly advancing field that has gained momentum in recent years, primarily encompassing chimeric antigen receptor T-cell (CAR-T) therapies, immune checkpoint inhibitors, and other modalities. However, its clinical efficacy remains limited, and drug resistance poses a significant challenge. Therefore, novel immunotherapeutic targets and agents need to be identified. Recently, N6-methyladenosine (m6A), the most prevalent RNA epitope modification, has emerged as a pivotal factor in various malignancies. Reportedly, m6A mutations influence the immunological microenvironment of hematological malignancies, leading to immune evasion and compromising the anti-tumor immune response in hematological malignancies. In this review, we comprehensively summarize the roles of the currently identified m6A modifications in various hematological malignancies, with a particular focus on their impact on the immune microenvironment. Additionally, we provide an overview of the research progress made in developing m6A-targeted drugs for hematological tumor therapy, to offer novel clinical insights.

Apoptosis, a Metabolic "Head-to-Head" between Tumor and T Cells: Implications for Immunotherapy

Induction of apoptosis represents a promising therapeutic approach to drive tumor cells to death. However, this poses challenges due to the intricate nature of cancer biology and the mechanisms employed by cancer cells to survive and escape immune surveillance. Furthermore, molecules released from apoptotic cells and phagocytes in the tumor microenvironment (TME) can facilitate cancer progression and immune evasion. Apoptosis is also a pivotal mechanism in modulating the strength and duration of anti-tumor T-cell responses. Combined strategies including molecular targeting of apoptosis, promoting immunogenic cell death, modulating immunosuppressive cells, and affecting energy pathways can potentially overcome resistance and enhance therapeutic outcomes. Thus, an effective approach for targeting apoptosis within the TME should delicately balance the selective induction of apoptosis in tumor cells, while safeguarding survival, metabolic changes, and functionality of T cells targeting crucial molecular pathways involved in T-cell apoptosis regulation. Enhancing the persistence and effectiveness of T cells may bolster a more resilient and enduring anti-tumor immune response, ultimately advancing therapeutic outcomes in cancer treatment. This review delves into the pivotal topics of this multifaceted issue and suggests drugs and druggable targets for possible combined therapies.

Revolutionizing Glioblastoma Treatment: A Comprehensive Overview of Modern Therapeutic Approaches

Glioblastoma is the most common malignant primary brain tumor in the adult population, with an average survival of 12.1 to 14.6 months. The standard treatment, combining surgery, radiotherapy, and chemotherapy, is not as efficient as we would like. However, the current possibilities are no longer limited to the standard therapies due to rapid advancements in biotechnology. New methods enable a more precise approach by targeting individual cells and antigens to overcome cancer. For the treatment of glioblastoma, these are gamma knife therapy, proton beam therapy, tumor-treating fields, EGFR and VEGF inhibitors, multiple RTKs inhibitors, and PI3K pathway inhibitors. In addition, the increasing understanding of the role of the immune system in tumorigenesis and the ability to identify tumor-specific antigens helped to develop immunotherapies targeting GBM and immune cells, including CAR-T, CAR-NK cells, dendritic cells, and immune checkpoint inhibitors. Each of the described methods has its advantages and disadvantages and faces problems, such as the inefficient crossing of the blood-brain barrier, various neurological and systemic side effects, and the escape mechanism of the tumor. This work aims to present the current modern treatments of glioblastoma.

Current and Future Trends of Colorectal Cancer Treatment: Exploring Advances in Immunotherapy

Cancer of the colon and rectum (CRC) has been identified among the three most prevalent types of cancer and cancer-related deaths for both sexes. Even though significant progress in surgical and chemotherapeutic techniques has markedly improved disease-free and overall survival rates in contrast to those three decades ago, recent years have seen a stagnation in these improvements. This underscores the need for new therapies aiming to augment patient outcomes. A number of emerging strategies, such as immune checkpoint inhibitors (ICIs) and adoptive cell therapy (ACT), have exhibited promising outcomes not only in preclinical but also in clinical settings. Additionally, a thorough appreciation of the underlying biology has expanded the scope of research into potential therapeutic interventions. For instance, the pivotal role of altered telomere length in early CRC carcinogenesis, leading to chromosomal instability and telomere dysfunction, presents a promising avenue for future treatments. Thus, this review explores the advancements in CRC immunotherapy and telomere-targeted therapies, examining potential synergies and how these novel treatment modalities intersect to potentially enhance each other's efficacy, paving the way for promising future therapeutic advancements.

Immune Regulation and Immune Therapy in Melanoma: Review with Emphasis on CD155 Signalling

Melanoma is commonly diagnosed in a younger population than most other solid malignancies and, in Australia and most of the world, is the leading cause of skin-cancer-related death. Melanoma is a cancer type with high immunogenicity; thus, immunotherapies are used as first-line treatment for advanced melanoma patients. Although immunotherapies are working well, not all the patients are benefitting from them. A lack of a comprehensive understanding of immune regulation in the melanoma tumour microenvironment is a major challenge of patient stratification. Overexpression of CD155 has been reported as a key factor in melanoma immune regulation for the development of therapy resistance. A more thorough understanding of the actions of current immunotherapy strategies, their effects on immune cell subsets, and the roles that CD155 plays are essential for a rational design of novel targets of anti-cancer immunotherapies. In this review, we comprehensively discuss current anti-melanoma immunotherapy strategies and the immune response contribution of different cell lineages, including tumour endothelial cells, myeloid-derived suppressor cells, cytotoxic T cells, cancer-associated fibroblast, and nature killer cells. Finally, we explore the impact of CD155 and its receptors DNAM-1, TIGIT, and CD96 on immune cells, especially in the context of the melanoma tumour microenvironment and anti-cancer immunotherapies.

Tumor biomarkers for diagnosis, prognosis and targeted therapy

Tumor biomarkers, the substances which are produced by tumors or the body's responses to tumors during tumorigenesis and progression, have been demonstrated to possess critical and encouraging value in screening and early diagnosis, prognosis prediction, recurrence detection, and therapeutic efficacy monitoring of cancers. Over the past decades, continuous progress has been made in exploring and discovering novel, sensitive, specific, and accurate tumor biomarkers, which has significantly promoted personalized medicine and improved the outcomes of cancer patients, especially advances in molecular biology technologies developed for the detection of tumor biomarkers. Herein, we summarize the discovery and development of tumor biomarkers, including the history of tumor biomarkers, the conventional and innovative technologies used for biomarker discovery and detection, the classification of tumor biomarkers based on tissue origins, and the application of tumor biomarkers in clinical cancer management. In particular, we highlight the recent advancements in biomarker-based anticancer-targeted therapies which are emerging as breakthroughs and promising cancer therapeutic strategies. We also discuss limitations and challenges that need to be addressed and provide insights and perspectives to turn challenges into opportunities in this field. Collectively, the discovery and application of multiple tumor biomarkers emphasized in this review may provide guidance on improved precision medicine, broaden horizons in future research directions, and expedite the clinical classification of cancer patients according to their molecular biomarkers rather than organs of origin.

Regulatory mechanisms of PD-1/PD-L1 in cancers

Immune evasion contributes to cancer growth and progression. Cancer cells have the ability to activate different immune checkpoint pathways that harbor immunosuppressive functions. The programmed death protein 1 (PD-1) and programmed cell death ligands (PD-Ls) are considered to be the major immune checkpoint molecules. The interaction of PD-1 and PD-L1 negatively regulates adaptive immune response mainly by inhibiting the activity of effector T cells while enhancing the function of immunosuppressive regulatory T cells (Tregs), largely contributing to the maintenance of immune homeostasis that prevents dysregulated immunity and harmful immune responses. However, cancer cells exploit the PD-1/PD-L1 axis to cause immune escape in cancer development and progression. Blockade of PD-1/PD-L1 by neutralizing antibodies restores T cells activity and enhances anti-tumor immunity, achieving remarkable success in cancer therapy. Therefore, the regulatory mechanisms of PD-1/PD-L1 in cancers have attracted an increasing attention. This article aims to provide a comprehensive review of the roles of the PD-1/PD-L1 signaling in human autoimmune diseases and cancers. We summarize all aspects of regulatory mechanisms underlying the expression and activity of PD-1 and PD-L1 in cancers, including genetic, epigenetic, post-transcriptional and post-translational regulatory mechanisms. In addition, we further summarize the progress in clinical research on the antitumor effects of targeting PD-1/PD-L1 antibodies alone and in combination with other therapeutic approaches, providing new strategies for finding new tumor markers and developing combined therapeutic approaches.

The synergistic immunotherapeutic impact of engineered CAR-T cells with PD-1 blockade in lymphomas and solid tumors: a systematic review

Currently, therapies such as chimeric antigen receptor-T Cell (CAR-T) and immune checkpoint inhibitors like programmed cell death protein-1 (PD-1) blockers are showing promising results for numerous cancer patients. However, significant advancements are required before CAR-T therapies become readily available as off-the-shelf treatments, particularly for solid tumors and lymphomas. In this review, we have systematically analyzed the combination therapy involving engineered CAR-T cells and anti PD-1 agents. This approach aims at overcoming the limitations of current treatments and offers potential advantages such as enhanced tumor inhibition, alleviated T-cell exhaustion, heightened T-cell activation, and minimized toxicity. The integration of CAR-T therapy, which targets tumor-associated antigens, with PD-1 blockade augments T-cell function and mitigates immune suppression within the tumor microenvironment. To assess the impact of combination therapy on various tumors and lymphomas, we categorized them based on six major tumor-associated antigens: mesothelin, disialoganglioside GD-2, CD-19, CD-22, CD-133, and CD-30, which are present in different tumor types. We evaluated the efficacy, complete and partial responses, and progression-free survival in both pre-clinical and clinical models. Additionally, we discussed potential implications, including the feasibility of combination immunotherapies, emphasizing the importance of ongoing research to optimize treatment strategies and improve outcomes for cancer patients. Overall, we believe combining CAR-T therapy with PD-1 blockade holds promise for the next generation of cancer immunotherapy.

Engineering PD-1-targeted small protein variants for in vitro diagnostics and in vivo PET imaging

BACKGROUND

Programmed cell death 1 (PD-1) belongs to immune checkpoint proteins ensuring negative regulation of the immune response. In non-small cell lung cancer (NSCLC), the sensitivity to treatment with anti-PD-1 therapeutics, and its efficacy, mostly correlated with the increase of tumor infiltrating PD-1+ lymphocytes. Due to solid tumor heterogeneity of PD-1+ populations, novel low molecular weight anti-PD-1 high-affinity diagnostic probes can increase the reliability of expression profiling of PD-1+ tumor infiltrating lymphocytes (TILs) in tumor tissue biopsies and in vivo mapping efficiency using immune-PET imaging.

METHODS

We designed a 13 kDa β-sheet Myomedin scaffold combinatorial library by randomization of 12 mutable residues, and in combination with ribosome display, we identified anti-PD-1 Myomedin variants (MBA ligands) that specifically bound to human and murine PD-1-transfected HEK293T cells and human SUP-T1 cells spontaneously overexpressing cell surface PD-1.

RESULTS

Binding affinity to cell-surface expressed human and murine PD-1 on transfected HEK293T cells was measured by fluorescence with LigandTracer and resulted in the selection of most promising variants MBA066 (hPD-1 KD = 6.9 nM; mPD-1 KD = 40.5 nM), MBA197 (hPD-1 KD = 29.7 nM; mPD-1 KD = 21.4 nM) and MBA414 (hPD-1 KD = 8.6 nM; mPD-1 KD = 2.4 nM). The potential of MBA proteins for imaging of PD-1+ populations in vivo was demonstrated using deferoxamine-conjugated MBA labeled with 68Galium isotope. Radiochemical purity of 68Ga-MBA proteins reached values 94.7-99.3% and in vitro stability in human serum after 120 min was in the range 94.6-98.2%. The distribution of 68Ga-MBA proteins in mice was monitored using whole-body positron emission tomography combined with computerized tomography (PET/CT) imaging up to 90 min post-injection and post mortem examined in 12 mouse organs. The specificity of MBA proteins was proven by co-staining frozen sections of human tonsils and NSCLC tissue biopsies with anti-PD-1 antibody, and demonstrated their potential for mapping PD-1+ populations in solid tumors.

CONCLUSIONS

Using directed evolution, we developed a unique set of small binding proteins that can improve PD-1 diagnostics in vitro as well as in vivo using PET/CT imaging.

LAG-3 : recent developments in combinational therapies in cancer

The study of anticancer immune responses and in particular the action of immune checkpoint inhibitors that overcome T cell inhibition has revolutionized metastatic patients' care. Unfortunately, many patients are resistant to these innovative immunotherapies. Over the last decade, several immune checkpoint inhibitors, currently available in the clinic, have been developed, such as anti-PD-1/PD-L1 or anti-CTLA-4. More recently, other immune checkpoints have been characterized, among them lymphocyte activation gene 3 (LAG-3). LAG-3 has been the subject of numerous therapeutic studies and may be involved in cancer-associated immune resistance phenomena. This review summarizes the latest knowledge on LAG-3 as an immunotherapeutic target, particularly in combination with standard or innovative therapies. Indeed, many studies are looking at combining LAG-3 inhibitors with chemotherapeutic, immunotherapeutic, radiotherapeutic treatments, or adoptive cell therapies to potentiate their antitumor effects and/or to overcome patients' resistance. We will particularly focus on the association therapies that are currently in phase III clinical trials and innovative combinations in preclinical phase. These new discoveries highlight the possibility of developing other types of therapeutic combinations currently unavailable in the clinic, which could broaden the therapeutic spectrum of personalized medicine.

Combining toll-like receptor agonists with immune checkpoint blockade affects antitumor vaccine efficacy

BACKGROUND

T cell checkpoint receptors are expressed when T cells are activated, and modulation of the expression or signaling of these receptors can alter the function of T cells and their antitumor efficacy. We previously found that T cells activated with cognate antigen had increases in the expression of PD-1, and this was attenuated in the presence of multiple toll-like receptor (TLR) agonists, notably TLR3 plus TLR9. In the current report, we sought to investigate whether combining TLR agonists with immune checkpoint blockade can further augment vaccine-mediated T cell antitumor immunity in murine tumor models.

METHODS

TLR agonists (TLR3 plus TLR9) and immune checkpoint inhibitors (antibodies targeting PD-1, CTLA-4, LAG-3, TIM-3 or VISTA) were combined and delivered with vaccines or vaccine-activated CD8+T cells to E.G7-OVA or MyC-CaP tumor-bearing mice. Tumors were assessed for growth and then collected and analyzed by flow cytometry.

RESULTS

Immunization of E.G7-OVA tumor-bearing mice with SIINFEKL peptide vaccine, coadministered with TLR agonists and αCTLA-4, demonstrated greater antitumor efficacy than immunization with TLR agonists or αCTLA-4 alone. Conversely, the antitumor efficacy was abrogated when vaccine and TLR agonists were combined with αPD-1. TLR agonists suppressed PD-1 expression on regulatory T cells (Tregs) and activated this population. Depletion of Tregs in tumor-bearing mice led to greater antitumor efficacy of this combination therapy, even in the presence of αPD-1. Combining vaccination with TLR agonists and αCTLA-4 or αLAG-3 showed greater antitumor than with combinations with αTIM-3 or αVISTA.

CONCLUSION

The combination of TLR agonists and αCTLA-4 or αLAG-3 can further improve the efficacy of a cancer vaccine, an effect not observed using αPD-1 due to activation of Tregs when αPD-1 was combined with TLR3 and TLR9 agonists. These data suggest that optimal combinations of TLR agonists and immune checkpoint blockade may improve the efficacy of human anticancer vaccines.

Decoding the potential role of regulatory T cells in sepsis-induced immunosuppression

Sepsis, a multiorgan dysfunction with high incidence and mortality, is caused by an imbalanced host-to-infection immune response. Organ-support therapy improves the early survival rate of sepsis patients. In the long term, those who survive the "cytokine storm" and its secondary damage usually show higher susceptibility to secondary infections and sepsis-induced immunosuppression, in which regulatory T cells (Tregs) are evidenced to play an essential role. However, the potential role and mechanism of Tregs in sepsis-induced immunosuppression remains elusive. In this review, we elucidate the role of different functional subpopulations of Tregs during sepsis and then review the mechanism of sepsis-induced immunosuppression from the aspects of regulatory characteristics, epigenetic modification, and immunometabolism of Tregs. Thoroughly understanding how Tregs impact the immune system during sepsis may shed light on preclinical research and help improve the translational value of sepsis immunotherapy.

Reducing PD-L1 Expression by Degraders and Downregulators as a Novel Strategy to Target the PD-1/PD-L1 Pathway

Targeting the programmed cell death protein-1 (PD-1)/programmed cell death-ligand 1 (PD-L1) pathway has evolved into one of the most promising strategies for tumor immunotherapy. Thus far, multiple monoclonal antibody drugs have been approved for treating a variety of tumors, while the development of small-molecule PD-1/PD-L1 inhibitors has lagged far behind, with only a few small-molecule inhibitors entering clinical trials. In addition to antibody drugs and small-molecule inhibitors, reducing the expression levels of PD-L1 has attracted extensive research interest as another promising strategy to target the PD-1/PD-L1 pathway. Herein, we analyze the structures and mechanisms of molecules that reduce PD-L1 expression and classify them as degraders and downregulators according to whether they directly bind to PD-L1. Moreover, we discuss the potential prospects for developing PD-L1-targeting drugs based on these molecules. It is hoped that this perspective will provide profound insights into the discovery of potent antitumor immunity drugs.

Exosomal PD-L1 in cancer and other fields: recent advances and perspectives

PD-1/PD-L1 signaling is a key factor of local immunosuppression in the tumor microenvironment. Immune checkpoint inhibitors targeting PD-1/PD-L1 signaling have achieved tremendous success in clinic. However, several types of cancer are particularly refractory to the anti-PD-1/PD-L1 treatment. Recently, a series of studies reported that IFN-γ can stimulate cancer cells to release exosomal PD-L1 (exoPD-L1), which possesses the ability to suppress anticancer immune responses and is associated with anti-PD-1 response. In this review, we introduce the PD-1/PD-L1 signaling, including the so-called 'reverse signaling'. Furthermore, we summarize the immune treatments of cancers and pay more attention to immune checkpoint inhibitors targeting PD-1/PD-L1 signaling. Additionally, we review the action mechanisms and regulation of exoPD-L1. We also introduce the function of exoPD-L1 as biomarkers. Finally, we review the methods for analyzing and quantifying exoPD-L1, the therapeutic strategies targeting exoPD-L1 to enhance immunotherapy and the roles of exoPD-L1 beyond cancer. This comprehensive review delves into recent advances of exoPD-L1 and all these findings suggest that exoPD-L1 plays an important role in both cancer and other fields.

Patients with Advanced or Metastasised Non-Small-Cell Lung Cancer with Viscum album L. Therapy in Addition to PD-1/PD-L1 Blockade: A Real-World Data Study

Immunotherapy with PD-1/PD-L1 inhibitors has significantly improved the survival rates of patients with metastatic non-small-cell lung cancer (NSCLC). Results of a real-world data study investigating add-on VA (Viscum album L.) to chemotherapy have shown an association with the improved overall survival of patients with NSCLC. We sought to investigate whether the addition of VA to PD-1/PD-L1 inhibitors in patients with advanced or metastasised NSCLC would have an additional survival benefit. In the present real-world data study, we enrolled patients from the accredited national registry, Network Oncology, with advanced or metastasised NSCLC. The reporting of data was performed in accordance with the ESMO-GROW criteria for the optimal reporting of oncological real-world evidence (RWE) studies. Overall survival was compared between patients receiving PD-1/PD-L1 inhibitor therapy (control, CTRL group) versus the combination of anti-PD-1/PD-L1 therapy and VA (combination, COMB group). An adjusted multivariate Cox proportional hazard analysis was performed to investigate variables associated with survival. From 31 July 2015 to 9 May 2023, 415 patients with a median age of 68 years and a male/female ratio of 1.2 were treated with anti-PD-1/PD-L1 therapy with or without add-on VA. Survival analyses included 222 (53.5%) patients within the CRTL group and 193 (46.5%) in the COMB group. Patients in the COMB group revealed a median survival of 13.8 months and patients in the CRTL group a median survival of 6.8 months (adjusted hazard ratio, aHR: 0.60, 95% CI: 0.43-0.85, p = 0.004) after adjustment for age, gender, tumour stage, BMI, ECOG status, oncological treatment, and PD-L1 tumour proportion score. A reduction in the adjusted hazard of death by 56% was seen with the addition of VA (aHR 0.44, 95% CI: 0.26-0.74, p = 0.002) in patients with PD-L1-positive tumours (tumour proportion score > 1%) treated with first-line anti-PD-1/PD-L1 therapy. Our findings suggest that add-on VA correlates with improved survival in patients with advanced or metastasised NSCLC who were treated with PD-1/PD-L1 inhibitors irrespective of age, gender, tumour stage, or oncological treatment. The underlying mechanisms may include the synergistic modulation of the immune response. A limitation of this study is the observational non-randomised study design, which only allows limited conclusions to be drawn and prospective randomised trials are warranted.

PD-L1/PD-1 pathway: a potential neuroimmune target for pain relief

Pain is a common symptom of many diseases with a high incidence rate. Clinically, drug treatment, as the main method to relieve pain at present, is often accompanied by different degrees of adverse reactions. Therefore, it is urgent to gain a profound understanding of the pain mechanisms in order to develop advantageous analgesic targets. The PD-L1/PD-1 pathway, an important inhibitory molecule in the immune system, has taken part in regulating neuroinflammation and immune response. Accumulating evidence indicates that the PD-L1/PD-1 pathway is aberrantly activated in various pain models. And blocking PD-L1/PD-1 pathway will aggravate pain behaviors. This review aims to summarize the emerging evidence on the role of the PD-L1/PD-1 pathway in alleviating pain and provide an overview of the mechanisms involved in pain resolution, including the regulation of macrophages, microglia, T cells, as well as nociceptor neurons. However, its underlying mechanism still needs to be further elucidated in the future. In conclusion, despite more deep researches are needed, these pioneering studies indicate that PD-L1/PD-1 may be a potential neuroimmune target for pain relief.

B cells and the coordination of immune checkpoint inhibitor response in patients with solid tumors

Immunotherapy profoundly changed the landscape of cancer therapy by providing long-lasting responses in subsets of patients and is now the standard of care in several solid tumor types. However, immunotherapy activity beyond conventional immune checkpoint inhibition is plateauing, and biomarkers are overall lacking to guide treatment selection. Most studies have focused on T cell engagement and response, but there is a growing evidence that B cells may be key players in the establishment of an organized immune response, notably through tertiary lymphoid structures. Mechanisms of B cell response include antibody-dependent cellular cytotoxicity and phagocytosis, promotion of CD4+ and CD8+ T cell activation, maintenance of antitumor immune memory. In several solid tumor types, higher levels of B cells, specific B cell subpopulations, or the presence of tertiary lymphoid structures have been associated with improved outcomes on immune checkpoint inhibitors. The fate of B cell subpopulations may be widely influenced by the cytokine milieu, with versatile roles for B-specific cytokines B cell activating factor and B cell attracting chemokine-1/CXCL13, and a master regulatory role for IL-10. Roles of B cell-specific immune checkpoints such as TIM-1 are emerging and could represent potential therapeutic targets. Overall, the expanding field of B cells in solid tumors of holds promise for the improvement of current immunotherapy strategies and patient selection.

Partial recovery of peripheral blood monocyte subsets in head and neck squamous cell carcinoma patients upon radio(chemo)therapy is associated with decreased plasma CXCL11

BACKGROUND

Head and neck squamous cell carcinoma (HNSCC) represents a common and heterogeneous malignancy of the oral cavity, pharynx and larynx. Surgery and radio(chemo)therapy are the standard treatment options and also have great influence on the composition of the tumor microenvironment and immune cell functions. However, the impact of radio(chemo)therapy on the distribution and characteristics of circulating monocyte subsets in HNSCC are not fully understood.

METHODS

Expression patterns of adhesion molecules and chemokine receptors CD11a (integrin-α L; LFA-1), CD11b (integrin-α M; Mac-1), CD11c (integrin-α X), CX3CR1 (CX3CL1 receptor) and checkpoint molecule PD-L1 (programmed cell death ligand-1) were investigated upon radio(chemo)therapeutic treatment using flow cytometry. Furthermore, comprehensive analysis of plasma cytokines was performed before and after treatment using ELISA measurements.

RESULTS

Our data reveal a partial recovery of circulating monocytes in HNSCC patients upon radio(chemo)therapeutic treatment, with differential effects of the individual therapy regimen. PD-L1 expression on non-classical monocytes significantly correlates with the individual plasma levels of chemokine CXCL11 (C-X-C motif chemokine 11).

CONCLUSIONS

Further comprehensive investigations on larger patient cohorts are required to elucidate the meaningfulness of peripheral blood monocyte subsets and chemokine CXCL11 as potential bioliquid indicators in HNSCC with regard to therapy response and the individual immunological situation.

D-mannose targets PD-1 to lysosomal degradation and enhances T cell-mediated anti-tumor immunity

High expression of programmed cell death protein 1 (PD-1), a typical immune checkpoint, results in dysfunction of T cells in tumor microenvironment. Antibodies and inhibitors against PD-1 or its ligand (PD-L1) have been widely used in various malignant tumors. However, the mechanisms by which PD-1 is regulated are not fully understood. Here, we report a mechanism of PD-1 degradation triggered by D-mannose and the universality of this mechanism in anti-tumor immunity. We show that D-mannose inactivates GSK3β via promoting phosphorylation of GSK3β at Ser9, thereby leading to TFE3 translocation to nucleus and subsequent PD-1 proteolysis induced by enhanced lysosome biogenesis. Notably, combination of D-mannose and PD-1 blockade exhibits remarkable tumor growth suppression attributed to elevated cytotoxicity activity of T cells in vivo. Furthermore, D-mannose treatment dramatically improves the therapeutic efficacy of MEK inhibitor (MEKi) trametinib in vivo. Our findings unveil a universally unrecognized anti-tumor mechanism of D-mannose by destabilizing PD-1 and provide strategies to enhance the efficacy of both immune checkpoint blockade (ICB) and MEKi -based therapies.

A Retrospective Review and Comprehensive Tumour Profiling of Advanced Non-Melanomatous Cutaneous Spindle Cell Neoplasms Treated with Immune-Checkpoint Inhibitors

Non-melanomatous cutaneous spindle cell neoplasms are a rare group of malignancies that present a diagnostic challenge, and for which there is a lack of consensus on how to best manage patients with advanced disease and only limited reports of immune-checkpoint inhibitor (ICI) responses. In this study, we performed a single-center retrospective review of treatment outcomes for all advanced non-melanomatous cutaneous spindle cell neoplasms treated with ICIs. Blinded histopathology reviews occurred to confirm each diagnosis. Comprehensive tumour profiling included whole exome sequencing for tumour mutational burden (TMB) and ultraviolet(UV) signatures, and immunohistochemistry for immune-cell infiltration (CD4/CD3/CD8/CD103/CD20) and immune-checkpoint expression (PD-L1/LAG3/TIGIT). Seven patients were identified. The objective response rate was 86% (6/7) with five complete responses (CR). Responses were durable with two patients in CR > 30 months after ICI commencement. All patients had high TMB and UV signatures. One patient had PD-L1 100% (combined positive score) with abundant immune-cell infiltration and LAG3 expression. In advanced non-melanomatous cutaneous spindle cell neoplasms, excellent responses to ICIs with durable disease control were observed. ICIs are worthy of further exploration in these patients. UV signatures and high TMB could be used to help select patients for treatment.