PD-L1 engagement on T cells promotes self-tolerance and suppression of neighboring macrophages and effector T cells in cancer

Multispecific Antibodies Targeting PD-1/PD-L1 in Cancer

The development of immune checkpoint inhibitors has revolutionized the treatment of patients with cancer. Targeting the programmed cell death protein 1 (PD-1)/programmed cell death 1 ligand 1(PD-L1) interaction using monoclonal antibodies has emerged as a prominent focus in tumor therapy with rapid advancements. However, the efficacy of anti-PD-1/PD-L1 treatment is hindered by primary or acquired resistance, limiting the effectiveness of single-drug approaches. Moreover, combining PD-1/PD-L1 with other immune drugs, targeted therapies, or chemotherapy significantly enhances response rates while exacerbating adverse reactions. Multispecific antibodies, capable of binding to different epitopes, offer improved antitumor efficacy while reducing drug-related side effects, serving as a promising therapeutic approach in cancer treatment. Several bispecific antibodies (bsAbs) targeting PD-1/PD-L1 have received regulatory approval, and many more are currently in clinical development. Additionally, tri-specific antibodies (TsAbs) and tetra-specific antibodies (TetraMabs) are under development. This review comprehensively explores the fundamental structure, preclinical principles, clinical trial progress, and challenges associated with bsAbs targeting PD-1/PD-L1.

Engineered MXene Biomaterials for Regenerative Medicine

MXene-based materials have attracted significant interest due to their distinct physical and chemical properties, which are relevant to fields such as energy storage, environmental science, and biomedicine. MXene has shown potential in the area of tissue regenerative medicine. However, research on its applications in tissue regeneration is still in its early stages, with a notable absence of comprehensive reviews. This review begins with a detailed description of the intrinsic properties of MXene, followed by a discussion of the various nanostructures that MXene can form, spanning from 0 to 3 dimensions. The focus then shifts to the applications of MXene-based biomaterials in tissue engineering, particularly in immunomodulation, wound healing, bone regeneration, and nerve regeneration. MXene's physicochemical properties, including conductivity, photothermal characteristics, and antibacterial properties, facilitate interactions with different cell types, influencing biological processes. These interactions highlight its potential in modulating cellular functions essential for tissue regeneration. Although the research on MXene in tissue regeneration is still developing, its versatile structural and physicochemical attributes suggest its potential role in advancing regenerative medicine.

Immuno-engineered macrophage membrane-coated nanodrug to restore immune balance for rheumatoid arthritis treatment

Current immunosuppressive therapies for rheumatoid arthritis (RA) lack disease specificity, primarily targeting inflammation while causing debilitating side effects. To address this limitation, we developed a biomimetic nanodrug MP@NEs/CT to induce antigen-specific immune tolerance for precise, effective and safe RA immunotherapy. MP@NEs/CT features a core of multiepitope citrullinated peptide (CitP) and triptolide (TPL) co-loaded nanoemulsion and coated with a macrophage membrane harvested from IFN-γ treated RAW264.7 cells. CitP, an RA autoantigen, specifically targets the immune response, while TPL acts as an immunosuppressant by inhibiting dendritic cells (DCs) maturation. IFN-γ treatment upregulates programmed death-ligand 1 (PD-L1) expression, facilitating MP@NEs/CT accumulation within inflamed tissues via programmed death-1 (PD-1) binding following intravenous administration. Additionally, the immune-engineered macrophage membrane sequesters proinflammatory cytokines, further dampening local inflammation. A significant reduction of CII-specific IgG levels in collagen-induced arthritis (CIA) mice model provides the evidence of CitP in restoring antigen-specific immune tolerance. Importantly, a low dose of TPL within MP@NEs/CT promotes tolerogenic DCs and generation of anti-inflammatory cytokines, ultimately leading to upregulation of antigen-specific regulatory T cells (Tregs) and B cells (Bregs) and a reduction in pro-inflammatory cytokine levels. Consequently, the nanodrug demonstrates synergistic and effective anti-inflammatory and immunosuppressive effects, alleviating autoimmune damage in a CIA mice model. STATEMENT OF SIGNIFICANCE: : Rheumatoid arthritis (RA) is a chronic autoimmune disease characterized by dysregulated immune responses, leading to synovial hyperplasia, tissue destruction, and irreversible disability. Early work in RA therapy mainly applying anti-inflammatory drugs which focuses on delaying joint deformity, but have no effects on the aberrant immune response. However, these drugs often require high doses and long-term administration, leading to potential adverse effects. In this work, we reported a therapeutic system that co-delivery of autoantigens with immune modulators promotes antigen-specific tolerance for effective and safe RA immunotherapy.

Cell-intrinsic PD-L1 signaling drives immunosuppression by myeloid-derived suppressor cells through IL-6/Jak/Stat3 in PD-L1-high lung cancer

BACKGROUND

Some patients with non-small-cell lung cancer (NSCLC) benefit from immune checkpoint inhibitors (ICIs) despite programmed death-ligand 1 (PD-L1) expression. To address the mechanism of ICI resistance in PD-L1-positive NSCLC, we investigated the role of tumor-cell-intrinsic function of PD-L1 in interleukin (IL)-6-mediated immunosuppression.

METHODS

Cohorts of NSCLC patients treated with ICI and public datasets were analyzed. PD-L1-overexpressing and PD-L1-knockdown NSCLC cells were submitted to RNA-seq, in vitro analyses, chromatin immunoprecipitation-qPCR, CUT&Tag, and biochemical assays. Human myeloid-derived suppressor cells (MDSCs) sorted from peripheral blood mononuclear cells were co-cultured with NSCLC cells and then assessed for their immunosuppressive activity on T-cells. Mouse Lewis lung carcinoma (LLC) cells with PD-L1 overexpression or knockdown were subcutaneously injected into wild-type or PD-1-knockout C57BL/6 mice in the presence of IL-6 and/or PD-1 blockade.

RESULTS

In the ICI cohort with RNA-seq data, the IL-6/Jak/Stat3 pathway was enriched, and IL-6 expression was higher in patients with PD-L1-high NSCLCs who did not respond to ICIs. In another cohort, a higher baseline serum IL-6 level was associated with poor clinical outcomes after ICI therapy. IL-6 expression and the IL-6/Jak/Stat3 pathway were enhanced in PD-L1-high NSCLCs in the ICI cohorts and The Cancer Genome Atlas analysis. IL-6 expression correlated positively with tumor-infiltrating MDSCs in NSCLCs. In NSCLC cells, PD-L1 activated Jak2/Stat3 signaling by binding to and inhibiting protein tyrosine phosphatase 1B. PD-L1 also bound to p-Stat3 in the nucleus, thus promoting the activity of p-Stat3 in the transcription of several cytokines (IL-6, TGF-β, TNF-α, IL-1β) and chemokines. PD-L1-overexpressing NSCLC cells enhanced the migration and immunosuppressive activity of human MDSCs in vitro, mediated by IL-6 and CXCL1. In both wild-type and PD-1-knockout mice, PD-L1-overexpressing LLC tumors were infiltrated by increased MDSCs with high immunosuppressive function, increased Tregs, and decreased granzyme B+ or IFNγ+ CD8 T-cells. These responses were mediated by IL-6 secreted from PD-L1-overexpressing tumor cells. Combined blockade of PD-1 and IL-6 was effective in tumor control and decreased MDSCs while increasing granzyme B+ or IFNγ+ CD8 T-cells.

CONCLUSIONS

The tumor-cell-intrinsic function of PD-L1 drives immunosuppression and tumor progression through the PD-L1/Jak/Stat3/IL-6/MDSC axis. This pathway represents a potential therapeutic target to improve ICI efficacy in PD-L1-high NSCLC.

Neoadjuvant chemoradiotherapy up-regulates PD-L1 in radioresistant colorectal cancer

Background

Combining radiotherapy (RT) with immune checkpoint inhibitors (ICIs) is a promising strategy that can enhance the therapeutic efficacy of ICIs. However, little is known about RT-induced changes in the expression of immune checkpoints, such as PD-L1, and their clinical implications in colorectal cancer (CRC). This study aimed to investigate the association between responsiveness to RT and changes in PD-L1 expression in human CRC tissue and cell lines.

Methods

Tissue specimens from preoperative biopsy via sigmoidoscopy and surgical resection were obtained from 24 patients with locally advanced rectal cancer (LARC) who underwent neoadjuvant chemoradiation therapy (CRT) between August 2016 and December 2017. Immunohistochemistry for PD-L1 in formalin-fixed paraffin-embedded tissue was performed from the endoscopic biopsy and surgical specimens. RNA sequencing was performed using 11 pairs of human LARC tissues before and after irradiation. After exposing human CRC cells to radiation, we investigated changes in the expression levels of PD-L1 and its regulatory signaling pathways.

Results

Patients were classified by tumor regression grade into responders (grade 2; 9 patients, 37.5 %) and non-responders (grades 3, 4, or 5; 15 patients, 62.5 %). In the non-responder group, 13 patients had low PD-L1 expression, but neoadjuvant CRT increased PD-L1 expression in 7 patients (53.9 %) (McNemar's test, p=0.034). CRT up-regulated PD-L1 in non-responder LARC tissues. Similarly, radiation increased PD-L1 in radioresistant DLD-1 cells more than in radiosensitive HCT116 cells, also affecting PD-L1-regulating genes and immune checkpoints in CRC cells. Conventional fractionated radiation treatment further increased PD-L1 in DLD-1 cells compared to HCT116 cells.

Conclusions

This study demonstrated that radiation induces an increase in PD-L1 expression, which is more pronounced in radioresistant CRC, proving the theoretical framework for a combined treatment strategy with a PD-L1 blockade for locally advanced rectal cancer.

Therapeutic Applications of Programmed Death Ligand 1 Inhibitors in Small Cell Lung Cancer

Background: Small cell lung cancer (SCLC) is an aggressive cancer with rapid progression, limited treatment success, and high relapse rates. Chemotherapy and radiation are standard treatments but often result in chemoresistance. PD-L1 inhibitors have gained attention for their role in enhancing tumor immunity. Methods: This review summarizes clinical trials involving PD-L1 inhibitors, such as atezolizumab, durvalumab, pembrolizumab, and nivolumab, in SCLC treatment. Key trials include IMpower133, CASPIAN, KEYNOTE-604, and CheckMate 331, focusing on survival outcomes and treatment efficacy. Results: Studies such as IMpower133 and CASPIAN demonstrate improved overall survival when PD-L1 inhibitors were added to platinum-based chemotherapy. However, outcomes in trials such as KEYNOTE-604 and CheckMate 331 varied, showing the need for refined patient selection. Adverse events (AEs) associated with these treatments were also noted. PD-L1 inhibitors offer promise in SCLC treatment, but efficacy varies across trials and patient groups. Future research should focus on better patient selection and overcoming resistance mechanisms. Addressing immune-related AEs is essential for optimizing treatment strategies.

Interferon-driven Metabolic Reprogramming and Tumor Microenvironment Remodeling

IFNs play a critical role in cancer biology, including impacting tumor cell behavior and instructing the tumor microenvironment (TME). IFNs recently have been shown to reprogram tumor metabolism through distinct mechanisms. Furthermore, IFNs shape the TME by modulating immune cell infiltration and function, contributing to the intricate interaction between the tumor and stromal cells. This review summarizes the effects of IFNs on metabolic reprogramming and their impacts on the function of immune cells within the TME, with a particular focus on the dual roles of IFNs in mediating both anti-tumor and pro-tumor immune responses. Understanding the significance of IFNs-mediated processes aids to advise future therapeutic strategies in cancer treatment.

Herpes stromal keratitis erodes the establishment of tissue-resident memory T cell pool in HSV-1 infected corneas

The recurrent herpes simplex virus-1 (HSV-1) infection of the cornea can cause the development of herpes stromal keratitis (HSK). This chronic immunoinflammatory condition is a major cause of infection-induced vision loss. The previous episodes of HSK increase the risk of future recurrences in the same cornea. However, not all HSV-1 infected corneas that shed infectious virus at the ocular surface develop HSK, suggesting that corneal HSV-1 infection may cause an establishment of protective immunity in HSV-1 infected corneas. However, upon recurrent corneal HSV-1 infection, the established protective immunity can get compromised, resulting in the development of HSK. In this study, we compared the quantity and quality of tissue-resident memory T (TRM) cells in HSV-1 infected corneas that did or did not develop HSK. Our results showed the predominance of TRM cell in the epithelium than in stroma of HSV-1 infected corneas. Furthermore, HSV-1 infected non-HSK corneas exhibited more CD4 and CD8 TRM cells than HSK corneas. The TRM cells in non-HSK than in HSK corneas were more effective in clearing the infectious virus upon secondary corneal HSV-1 infection. Our results demonstrate the differential quantity and quality of TRM cells in HSV-1 infected corneas that did or did not develop HSK.

Immune-mediated liver injury from checkpoint inhibitors: mechanisms, clinical characteristics and management

Immunotherapy has changed the treatment landscape for patients with cancer in the past decade. Immune checkpoint inhibitor (ICI)-based therapies have proven effective in a range of malignancies, including liver and gastrointestinal cancers, but they can cause diverse off-target organ toxicities. With the increasingly wider application of these drugs, immune-mediated liver injury from ICIs has become a commonly encountered challenge in clinical hepatology and gastroenterology. In this Review, we discuss the evidence from human and animal studies on the immunological mechanisms of immune-mediated liver injury from ICIs and summarize its clinical features and practical considerations for its management.

An encodable amino acid for targeted photocatalysis

Photocatalysts are excellent scaffolds for the light-mediated control of bioactive molecules. Current photocatalytic structures are not compatible with genetic encoding and therefore cannot be directly incorporated into the sequences of native proteins. Herein, we developed new amino acids incorporating Si-rosamine photocatalytic units, and introduced them via aminoacylation of tRNAs into specific positions of different proteins to enable targeted photocatalytic reactions in defined populations of immune cells.

Interactions of human milk oligosaccharides with the immune system

Human milk oligosaccharides (HMOs) are abundant, diverse and complex sugars present in human breast milk. HMOs are well-characterized barriers to microbial infection and by modulating the human microbiome they are also thought to be nutritionally beneficial to the infant. The structural variety of over 200 HMOs, including neutral, fucosylated and sialylated forms, allows them to interact with the immune system in various ways. Clinically, HMOs impact allergic diseases, reducing autoimmune and inflammatory responses, and offer beneficial support to the preterm infant immune health. This review examines the HMO composition and associated immunomodulatory effects, including interactions with immune cell receptors and gut-associated immune responses. These immunomodulatory properties highlight the potential for HMO use in early stage immune development and for use as novel immunotherapeutics. HMO research is rapidly evolving and promises innovative treatments for immune-related conditions and improved health outcomes.

Discovery of a common light chain bispecific antibody targeting PD-1 and PD-L1 by Hybridoma-to-Phage-to-Yeast (H2PtY) platform

Background

Therapeutic antibody drugs targeting the PD-1 pathway are generally characterized by relatively low response rates and susceptibility to drug resistance during clinical application. Therefore, there is an urgent need for alternative therapeutic strategies to increase the immune response rate. Bispecific antibodies co-targeting PD-1 and PD-L1 may have greater potential to improve the efficacy of the immune checkpoint pathway.

Method

In this study, we developed a potent humanized common light chain (CLC) IgG shape bispecific antibody (bsAb), named JMB2005, based on Hybridoma-to-Phage-to-Yeast platform. The platform allowed us to discover CLC bsAb from traditional mice for any pair of given targets.

Results

JMB2005 exhibited favorable developability, good manufacturing property, and satisfactory efficacy, which could be given via subcutaneous injection at the concentration of 120 mg/mL. Mechanistically, JMB2005 could bridge tumor cells and T cells with both Fab arms and promote T-cells to function as direct tumor cell killers. It could also promote T cell activation by blocking the binding of PD-L1 to CD80. Furthermore, JMB2005 has exhibited a favorable half-life and has demonstrated promising anti-tumor therapeutic efficacy in vivo.

Conclusion

Consequently, the present study showed that the novel humanized CLC bsAb JMB2005 may represent a novel therapeutic agent of great clinical potential.

The association between immune cells and breast cancer: insights from Mendelian randomization and meta-analysis

BACKGROUND

Breast cancer (BC) is the most common cancer among women worldwide, with 2.3 million new cases and 685 000 deaths annually. It has the highest incidence in North America, Europe, and Australia and lower rates in parts of Asia and Africa. Risk factors include age, family history, hormone replacement therapy, obesity, alcohol consumption, and lack of physical activity. BRCA1 and BRCA2 gene mutations significantly increase the risk. The 5-year survival rate is over 90% in developed countries but lower in developing ones. Early screening and diagnosis, using mammography and MRI, are crucial for reducing mortality. In recent years, significant progress has been made in studying BC immunophenotyping, particularly in multicolor flow cytometry, molecular imaging techniques, and tumor microenvironment analysis. These technologies improve diagnosis, classification, and detection of minimal residual disease. Novel immunotherapies targeting the tumor microenvironment, like CAR-T cell therapy, show high efficiency and fewer side effects. High levels of tumor-infiltrating lymphocytes correlate with better prognosis, while immune checkpoint molecules (PD-1, PD-L1) help cancer cells evade the immune system. Tumor-associated macrophages promote invasion and metastasis. Blocking molecules like CTLA-4, LAG-3, and TIM-3 enhance antitumor responses, and cytokines like IL-10 and TGF-β aid tumor growth and immune evasion. Mendelian randomization (MR) studies use genetic variants to reduce confounding bias and avoid reverse causation, providing robust causal inferences about immune cell phenotypes and BC. This approach supports the development of precision medicine and personalized treatment strategies for BC.

METHODS

This study aims to conduct MR analysis on 731 immune cell phenotypes with BC in the BCAC and Finngen R10 datasets, followed by a meta-analysis of the primary results using the inverse-variance weighted (IVW) method and multiple corrections for the significance P -values from the meta-analysis. Specifically, the study is divided into three parts: First, data on 731 immune cell phenotypes and BC are obtained and preprocessed from the GWAS Catalog and Open GWAS (BCAC) and the Finngen R10 databases. Second, MR analysis is performed on the 731 immune cell phenotypes with BC data from the BCAC and Finngen R10 databases, followed by a meta-analysis of the primary results using the IVW method, with multiple corrections for the significance P -values from the meta-analysis. Finally, the positively identified immune cell phenotypes are used as outcome variables, and BC as the exposure variable for reverse MR validation.

RESULTS

The study found that two immune phenotypes exhibited strong significant associations in MR analysis combined with meta-analysis and multiple corrections. For the immune phenotype CD3 on CD28+ CD4-CD8- T cells, the results were as follows: in the BCAC dataset, the IVW result was odds ratio (OR) = 0.942 (95% CI: 0.915-0.970, P =6.76×10 -5 ), β =-0.059; MR Egger result was β =-0.095; and the weighted median result was β =-0.060. In the Finngen R10 dataset, the IVW result was OR=0.956 (95% CI: 0.907-1.01, P =0.092), β =-0.045; MR Egger result was β =-0.070; and weighted median result was β =-0.035. The β values were consistent in direction across all three MR methods in both datasets. The meta-analysis of the IVW results from both datasets showed OR=0.945 (95% CI: 0.922-0.970, P =1.70×10 -5 ). After Bonferroni correction, the significant P- value was P =0.01, confirming the immune phenotype as a protective factor against BC. For the immune phenotype HLA DR on CD33- HLA DR+, the results were as follows: in the BCAC dataset, the IVW result was OR=0.977 (95% CI: 0.964-0.990, P =7.64×10 -4 ), β =-0.023; MR Egger result was β =-0.016; and the weighted median result was β =-0.019. In the Finngen R10 dataset, the IVW result was OR=0.960 (95% CI: 0.938-0.983, P =6.51×10 -4 ), β =-0.041; MR Egger result was β =-0.064; and weighted median result was β =-0.058. The β values were consistent in direction across all three MR methods in both datasets. The meta-analysis of the IVW results from both datasets showed OR=0.973 (95% CI: 0.961-0.984, P =3.80×10 -6 ). After Bonferroni correction, the significant P -value was P =0.003, confirming this immune phenotype as a protective factor against BC. When the immune cell phenotypes CD3 on CD28+ CD4-CD8- T cells and HLA DR on CD33- HLA DR+ were used as outcomes and BC was used as exposure, the data processing and analysis procedures were the same. The MR analysis results are as follows: data from the FinnGen database regarding the effect of positive immune phenotypes on malignant neoplasm of the breast indicated a β coefficient of -0.011, OR = 0.99 (95% CI: -0.117-0.096, P =0.846); data from the BCAC database regarding favorable immune phenotypes for BC demonstrated a β coefficient of -0.052, OR=0.095 (95% CI: -0.144-0.040, P =0.266). The results suggest insufficient evidence in both databases to indicate that BC inversely affects these two immune cell phenotypes.

CONCLUSIONS

Evidence suggests that the immune cell phenotypes CD3 on CD28+ CD4-CD8- T cells and HLA DR on CD33- HLA DR+ protect against BC. This protective effect may be achieved through various mechanisms, including enhancing immune surveillance to recognize and eliminate tumor cells; secreting cytokines to inhibit tumor cell proliferation and growth directly; triggering apoptotic pathways in tumor cells to reduce their number; modulating the tumor microenvironment to make it unfavorable for tumor growth and spread; activating other immune cells to boost the overall immune response; and inhibiting angiogenesis to reduce the tumor's nutrient supply. These mechanisms work together to help protect BC patients and slow disease progression. Both immune cell phenotypes are protective factors for BC patients and can be targeted to enhance their function and related pathways for BC treatment.

Reversal of Endothelial Cell Anergy by T Cell-Engaging Bispecific Antibodies

Objectives: Reduced expression of adhesion molecules in tumor vasculature can limit infiltration of effector T cells. To improve T cell adhesion to tumor endothelial cell (EC) antigens and enhance transendothelial migration, we developed bispecific, T-cell engaging antibodies (bsAb) that activate T cells after cross-linking with EC cell surface antigens. Methods: Recombinant T-cell stimulatory anti-VEGFR2-anti-CD3 and costimulatory anti-TIE2-anti-CD28 or anti-PD-L1-anti-CD28 bsAb were engineered and expressed. Primary lines of human umbilical vein endothelial cells (HUVEC) that constitutively express VEGFR2 and TIE2 growth factor receptors and PD-L1, but very low levels of adhesion molecules, served as models for anergic tumor EC. Results: In cocultures with HUVEC, anti-VEGFR2-anti-CD3 bsAb increased T cell binding and elicited rapid T cell activation. The release of proinflammatory cytokines TNF-α, IFN-γ, and IL-6 was greatly augmented by the addition of anti-TIE2-anti-CD28 or anti-PD-L1-anti-CD28 costimulatory bsAb. Concomitantly, T cell-released cytokines upregulated E-selectin, ICAM1, and VCAM1 adhesion molecules on HUVEC. HUVEC cultured in breast cancer cell-conditioned medium to mimic the influence of tumor-secreted factors were similarly activated by T cell-engaging bsAb. Migration of T cells in transwell assays was significantly increased by anti-VEGFR2-anti-CD3 bsAb. The combination with costimulatory anti-TIE2-anti-CD28 bsAb augmented activation and proliferation of migrated T cells and their cytotoxic capacity against spheroids of the MCF-7 breast cancer cell line seeded in the lower transwell chamber. Conclusions: T cells activated by anti-VEGFR2-anti-CD3 and costimulatory EC-targeting bsAb can reverse the energy of quiescent EC in vitro, resulting in improved T cell migration through an EC layer.

Notch Signaling and PD-1/PD-L1 Interaction in Hepatocellular Carcinoma: Potentialities of Combined Therapies

Immunotherapy has shown significant improvement in the survival of patients with hepatocellular carcinoma (HCC) compared to TKIs as first-line treatment. Unfortunately, approximately 30% of HCC exhibits intrinsic resistance to ICIs, making new therapeutic combinations urgently needed. The dysregulation of the Notch signaling pathway observed in HCC can affect immune cell response, reducing the efficacy of cancer immunotherapy. Here, we provide an overview of how Notch signaling regulates immune responses and present the therapeutic rationale for combining Notch signaling inhibition with ICIs to improve HCC treatment. Moreover, we propose using exosomes as non-invasive tools to assess Notch signaling activation in hepatic cancer cells, enabling accurate stratification of patients who can benefit from combined strategies.

Quantitative analysis of immune cells within the tumor microenvironment of glioblastoma and their relevance for prognosis

Glioblastoma (GBM) is a high malignant tumor with no effective treatment. To comprehensively characterize the landscape of immune cells in GBM and evaluate their correlation with prognosis, we developed a multispectral fluorescent imaging pipeline that included tumor-infiltrating lymphocytic markers (CD3, CD4, CD8, FOXP3, NKP46), immune checkpoint markers (PD-1, PD-L1), and markers to characterize myeloid cells (CD68, CD66b, CD163, HLA-DR), to spatially quantify 18 immune cell subsets in 21 GBM cases. We found that macrophages are the most abundant in GBM microenvironment, followed by T cells and neutrophils, while NK and NKT cells are the least. Previously unreported CD8+ Treg, PD-L1+ neutrophils, and high proportion of PD-1+ NK and PD-1+ T cells were also detected. Single high densities of PD-1+CD8+ T cells, neutrophils, and PD-L1-expressing CD68+ cells were associated with longer survival. Moreover, closer proximity of T cells to PD-L1+ macrophages or PD-L1+ neutrophils were associated with poor prognosis. Correlative analysis revealed circulating PMN-MDSC and e-MDSC were positively correlated with intratumoral M2 macrophages, while circulating NK cells were inversely associated with infiltrating CD4+ Treg cells in GBM patients. Our findings highlighted the potential roles of infiltrating immune cells in prognosis prediction and developing novel immunotherapeutic strategies for GBM patients.

Self-delivering RNAi immunotherapeutic PH-762 silences PD-1 to generate local and abscopal antitumor efficacy

Objective

Immunotherapeutic inhibition of PD-1 by systemically administered monoclonal antibodies is widely used in cancer treatment, but it may cause severe immune-related adverse events (irSAEs). Neoadjuvant PD-1 inhibition before surgery has shown promise in reducing recurrence by stimulating durable antitumor immunity. Local intratumoral (IT) immunotherapy is a potential strategy to minimize irSAEs, but antibodies have limited tumor penetration, making them less suitable for this approach. Therapeutic self-delivering RNAi (INTASYL) is an emerging modality well-suited for neoadjuvant immunotherapy. This study presents preclinical proof-of-concept for PH-762, an INTASYL designed to silence PD-1, currently in clinical development for advanced cutaneous malignancies (ClinicalTrials.gov#NCT06014086).

Methods and analysis

PH-762 pharmacology was characterized in vitro, and in vivo antitumor efficacy was evaluated using a murine analogue (mPH-762) in syngeneic tumor models with varying PD-1 responsiveness. Bilateral Hepa1-6 models assessed abscopal effects of local treatment. Ex vivo analyses explored mechanisms of direct and abscopal efficacy.

Results

PH-762 was rapidly internalized by human T cells, silencing PD-1 mRNA and decreasing PD-1 surface protein, enhancing TCR-stimulated IFN-γ and CXCL10 secretion. In vivo, IT mPH-762 provided robust antitumor efficacy, local and lymphatic biodistribution, and was well tolerated. Ex vivo analyses revealed that IT mPH-762 depleted PD-1 protein, promoted leukocyte and T cell infiltration, and correlated with tumor control. IT mPH-762 also demonstrated efficacy against untreated distal tumors (abscopal effect) by priming systemic antitumor immunity.

Conclusion

These data support PH-762 as a promising candidate for neoadjuvant immunotherapy in clinical studies.

Extracellular vesicles in cancers: mechanisms, biomarkers, and therapeutic strategies

Extracellular vesicles (EVs) composed of various biologically active constituents, such as proteins, nucleic acids, lipids, and metabolites, have emerged as a noteworthy mode of intercellular communication. There are several categories of EVs, including exosomes, microvesicles, and apoptotic bodies, which largely differ in their mechanisms of formation and secretion. The amount of evidence indicated that changes in the EV quantity and composition play a role in multiple aspects of cancer development, such as the transfer of oncogenic signals, angiogenesis, metabolism remodeling, and immunosuppressive effects. As EV isolation technology and characteristics recognition improve, EVs are becoming more commonly used in the early diagnosis and evaluation of treatment effectiveness for cancers. Actually, EVs have sparked clinical interest in their potential use as delivery vehicles or vaccines for innovative antitumor techniques. This review will focus on the function of biological molecules contained in EVs linked to cancer progression and their participation in the intricate interrelationship within the tumor microenvironment. Furthermore, the potential efficacy of an EV-based liquid biopsy and delivery cargo for treatment will be explored. Finally, we explicitly delineate the limitations of EV-based anticancer therapies and provide an overview of the clinical trials aimed at improving EV development.

Spatial heterogeneity of infiltrating immune cells in the tumor microenvironment of non-small cell lung cancer

Tumor-infiltrating lymphocytes (TILs) are essential components of the tumor microenvironment (TME) of non-small cell lung cancer (NSCLC). Still, it is difficult to describe due to their heterogeneity. In this study, five cell markers from NSCLC patients were analyzed. We segmented tumor cells (TCs) and TILs using Efficientnet-B3 and explored their quantitative information and spatial distribution. After that, we simulated multiplex immunohistochemistry (mIHC) by overlapping continuous single chromogenic IHCs slices. As a result, the proportion and the density of programmed cell death-ligand 1 (PD-L1)-positive TCs were the highest in the core. CD8+ T cells were the closest to the tumor (median distance: 41.71 μm), while PD-1+T cells were the most distant (median distance: 62.2μm), and our study found that most lymphocytes clustered together within the peritumoral range of 10-30 μm where cross-talk with TCs could be achieved. We also found that the classification of TME could be achieved using CD8+ T-cell density, which is correlated with the prognosis of patients. In addition, we achieved single chromogenic IHC slices overlap based on CD4-stained IHC slices. We explored the number and spatial distribution of cells in heterogeneous TME of NSCLC patients and achieved TME classification. We also found a way to show the co-expression of multiple molecules economically.

Leucine zipper-based immunomagnetic purification of CAR T cells displaying multiple receptors

Resistance to chimaeric antigen receptor (CAR) T cell therapy develops through multiple mechanisms, most notably antigen loss and tumour-induced immune suppression. It has been suggested that T cells expressing multiple CARs may overcome the resistance of tumours and that T cells expressing receptors that switch inhibitory immune-checkpoint signals into costimulatory signals may enhance the activity of the T cells in the tumour microenvironment. However, engineering multiple features into a single T cell product is difficult because of the transgene-packaging constraints of current gene-delivery vectors. Here we describe a cell-sorting method that leverages leucine zippers for the selective single-step immunomagnetic purification of cells co-transduced with two vectors. Such 'Zip sorting' facilitated the generation of T cells simultaneously expressing up to four CARs and coexpressing up to three 'switch' receptors. In syngeneic mouse models, T cells with multiple CARs and multiple switch receptors eliminated antigenically heterogeneous populations of leukaemia cells coexpressing multiple inhibitory ligands. By combining diverse therapeutic strategies, Zip-sorted multi-CAR multi-switch-receptor T cells can overcome multiple mechanisms of CAR T cell resistance.

Optimized full-spectrum flow cytometry panel for deep immunophenotyping of murine lungs

The lung immune system consists of both resident and circulating immune cells that communicate intricately. The immune system is activated by exposure to bacteria and viruses, when cancer initiates in the lung (primary lung cancer), or when metastases of other cancer types, including breast cancer, spread to and develop in the lung (secondary lung cancer). Thus, in these pathological situations, a comprehensive and quantitative assessment of changes in the lung immune system is of paramount importance for understanding mechanisms of infectious diseases, lung cancer, and metastasis but also for developing efficacious treatments. Unfortunately, lung tissue exhibits high autofluorescence, and this high background signal makes high-parameter flow cytometry analysis complicated. Here, we provide an optimized 30-parameter antibody panel for the analysis of all major immune cell types and states in normal and metastatic murine lungs using spectral flow cytometry.

TMED inhibition suppresses cell surface PD-1 expression and overcomes T cell dysfunction

BACKGROUND

Blockade of the programmed cell death protein 1 (PD-1) immune checkpoint (ICB) is revolutionizing cancer therapy, but little is known about the mechanisms governing its expression on CD8 T cells. Because PD-1 is induced during activation of T cells, we set out to uncover regulators whose inhibition suppresses PD-1 abundance without adversely impacting on T cell activation.

METHODS

To identify PD-1 regulators in an unbiased fashion, we performed a whole-genome, fluorescence-activated cell sorting (FACS)-based CRISPR-Cas9 screen in primary murine CD8 T cells. A dual-readout design using the activation marker CD137 allowed us to uncouple genes involved in PD-1 regulation from those governing general T cell activation.

RESULTS

We found that the inactivation of one of several members of the TMED/EMP24/GP25L/p24 family of transport proteins, most prominently TMED10, reduced PD-1 cell surface abundance, thereby augmenting T cell activity. Another client protein was cytotoxic T lymphocyte-associated protein 4 (CTLA-4), which was also suppressed by TMED inactivation. Treatment with TMED inhibitor AGN192403 led to lysosomal degradation of the TMED-PD-1 complex and reduced PD-1 abundance in tumor-infiltrating CD8 T cells (TIL) in mice, thus reversing T cell dysfunction. Clinically corroborating these findings, single-cell RNA analyses revealed a positive correlation between TMED expression in CD8 TIL, and both a T cell dysfunction signature and lack of ICB response. Similarly, patients receiving a TIL product with high TMED expression had a shorter overall survival.

CONCLUSION

Our results uncover a novel mechanism of PD-1 regulation, and identify a pharmacologically tractable target whose inhibition suppresses PD-1 abundance and T cell dysfunction.

Antibody-displaying extracellular vesicles for targeted cancer therapy

Extracellular vesicles (EVs) function as natural delivery vectors and mediators of biological signals across tissues. Here, by leveraging these functionalities, we show that EVs decorated with an antibody-binding moiety specific for the fragment crystallizable (Fc) domain can be used as a modular delivery system for targeted cancer therapy. The Fc-EVs can be decorated with different types of immunoglobulin G antibody and thus be targeted to virtually any tissue of interest. Following optimization of the engineered EVs by screening Fc-binding and EV-sorting moieties, we show the targeting of EVs to cancer cells displaying the human epidermal receptor 2 or the programmed-death ligand 1, as well as lower tumour burden and extended survival of mice with subcutaneous melanoma tumours when systemically injected with EVs displaying an antibody for the programmed-death ligand 1 and loaded with the chemotherapeutic doxorubicin. EVs with Fc-binding domains may be adapted to display other Fc-fused proteins, bispecific antibodies and antibody-drug conjugates.

Expression, regulation, and function of PD-L1 on non-tumor cells in the tumor microenvironment

Antiprogrammed death ligand 1 (PD-L1) therapy is a leading immunotherapy, but only some patients with solid cancers benefit. Overwhelming evidence has revealed that PD-L1 is expressed on various immune cells in the tumor microenvironment (TME), including macrophages, dendritic cells, and regulatory T cells, modulating tumor immunity and influencing tumor progression. PD-L1 can also be located on tumor cell membranes as well as in exosomes and cytoplasm. Accordingly, the dynamic expression and various forms of PD-L1 might explain the therapy's limited efficacy and resistance. Herein a systematic summary of the expression of PD-L1 on different immune cells and their regulatory mechanisms is provided to offer a solid foundation for future studies.

Cell Identity and Spatial Distribution of PD-1/PD-L1 Blockade Responders

The programmed death 1 (PD-1)/programmed death ligand 1 (PD-L1) axis inhibits T cell activity, impairing anti-tumor immunity. Blocking this axis with therapeutic antibodies is one of the most promising anti-tumor immunotherapies. It has long been recognized that PD-1/PD-L1 blockade reinvigorates exhausted T (TEX) cells already present in the tumor microenvironment (TME). However, recent advancements in high-throughput gene sequencing and bioinformatic tools have provided researchers with a more granular and dynamic insight into PD-1/PD-L1 blockade-responding cells, extending beyond the TME and TEX populations. This review provides an update on the cell identity, spatial distribution, and treatment-induced spatiotemporal dynamics of PD-1/PD-L1 blockade responders. It also provides a synopsis of preliminary reports of potential PD-1/PD-L1 blockade responders other than T cells to depict a panoramic picture. Important questions to answer in further studies and the translational and clinical potential of the evolving understandings are also discussed.

Intra-tumoral and peripheral blood TIGIT and PD-1 as immune biomarkers in nodular lymphocyte predominant Hodgkin lymphoma

In classical Hodgkin lymphoma (cHL), responsiveness to immune-checkpoint blockade (ICB) is associated with specific tumor microenvironment (TME) and peripheral blood features. The role of ICB in nodular lymphocyte predominant Hodgkin lymphoma (NLPHL) is not established. To gain insights into its potential in NLPHL, we compared TME and peripheral blood signatures between HLs using an integrative multiomic analysis. A discovery/validation approach in 121 NLPHL and 114 cHL patients highlighted >2-fold enrichment in programmed cell death-1 (PD-1) and T-cell Ig and ITIM domain (TIGIT) gene expression for NLPHL versus cHL. Multiplex imaging showed marked increase in intra-tumoral protein expression of PD-1+ (and/or TIGIT+) CD4+ T-cells and PD-1+CD8+ T-cells in NLPHL compared to cHL. This included T-cells that rosetted with lymphocyte predominant (LP) and Hodgkin Reed-Sternberg (HRS) cells. In NLPHL, intra-tumoral PD-1+CD4+ T-cells frequently expressed TCF-1, a marker of heightened T-cell response to ICB. The peripheral blood signatures between HLs were also distinct, with higher levels of PD-1+TIGIT+ in TH1, TH2, and regulatory CD4+ T-cells in NLPHL versus cHL. Circulating PD-1+CD4+ had high levels of TCF-1. Notably, in both lymphomas, highly expanded populations of clonal TIGIT+PD-1+CD4+ and TIGIT+PD-1+CD8+ T-cells in the blood were also present in the TME, indicating that immune-checkpoint expressing T-cells circulated between intra-tumoral and blood compartments. In in vitro assays, ICB was capable of reducing rosette formation around LP and HRS cells, suggesting that disruption of rosetting may be a mechanism of action of ICB in HL. Overall, results indicate that further evaluation of ICB is warranted in NLPHL.

PD-L1 and PD-1 Are Associated with Clinical Outcomes and Alveolar Immune Cell Activation in Acute Respiratory Distress Syndrome

The relationship between the PD-L1 (Programmed Death-Ligand 1)/PD-1 pathway, lung inflammation, and clinical outcomes in acute respiratory distress syndrome (ARDS) is poorly understood. We sought to determine whether PD-L1/PD-1 in the lung or blood is associated with ARDS and associated severity. We measured soluble PD-L1 (sPD-L1) in plasma and lower respiratory tract samples (ARDS1 [n = 59] and ARDS2 [n = 78]) or plasma samples alone (ARDS3 [n = 149]) collected from subjects with ARDS and tested for associations with mortality using multiple regression. We used mass cytometry to measure PD-L1/PD-1 expression and intracellular cytokine staining in cells isolated from BAL fluid (n = 18) and blood (n = 16) from critically ill subjects with or without ARDS enrolled from a fourth cohort. Higher plasma concentrations of sPD-L1 were associated with mortality in ARDS1, ARDS2, and ARDS3. In contrast, higher concentrations of sPD-L1 in the lung were either not associated with mortality (ARDS2) or were associated with survival (ARDS1). Alveolar PD-1POS T cells had more intracellular cytokine staining than PD-1NEG T cells. Subjects without ARDS had a higher ratio of PD-L1POS alveolar macrophages to PD-1POS T cells than subjects with ARDS. We conclude that sPD-L1 may have divergent cellular sources and/or functions in the alveolar versus blood compartments, given distinct associations with mortality. Alveolar leukocyte subsets defined by PD-L1 or PD-1 cell-surface expression have distinct cytokine secretion profiles, and the relative proportions of these subsets are associated with ARDS.

Extracellular vesicles reshape the tumor microenvironment to improve cancer immunotherapy: Current knowledge and future prospects

Tumor immunotherapy has revolutionized cancer treatment, but limitations remain, including low response rates and immune complications. Extracellular vesicles (EVs) are emerging as a new class of therapeutic agents for various diseases. Recent research shows that changes in the amount and composition of EVs can reshape the tumor microenvironment (TME), potentially improving the effectiveness of immunotherapy. This exciting discovery has sparked clinical interest in using EVs to enhance the immune system's response to cancer. In this Review, we delve into the world of EVs, exploring their origins, how they're generated, and their complex interactions within the TME. We also discuss the crucial role EVs play in reshaping the TME during tumor development. Specifically, we examine how their cargo, including molecules like PD-1 and non-coding RNA, influences the behavior of key immune cells within the TME. Additionally, we explore the current applications of EVs in various cancer therapies, the latest advancements in engineering EVs for improved immunotherapy, and the challenges faced in translating this research into clinical practice. By gaining a deeper understanding of how EVs impact the TME, we can potentially uncover new therapeutic vulnerabilities and significantly enhance the effectiveness of existing cancer immunotherapies.

Perioperative chemoimmunotherapy induces strong immune responses and long-term survival in patients with HLA class I-deficient non-small cell lung cancer

BACKGROUND

Loss of human leukocyte antigen (HLA) class I expression and loss of heterozygosity (LOH) are common events implicated in the primary resistance of non-small cell lung cancer (NSCLC) to immunotherapy. However, there is no data on perioperative chemoimmunotherapy (ChIO) efficacy or response mechanisms in the context of HLA class I defects.

METHODS

Baseline HLA class I tumor status (HLA-deficient (HLA-DEF) or HLA-proficient (HLA-PRO)) was determined by DNA LOH combined with immunohistochemistry for protein levels in tissue of 24 patients with NSCLC treated with perioperative nivolumab plus chemotherapy from NADIM trial (NCT03081689). We integrated HLA tumor status with molecular data (programmed death-ligand 1 (PD-L1), TMB, TCR repertoire, TILs populations, bulk RNA-seq, and spatial transcriptomics (ST)) and clinical outcomes (pathological response and survival data) to study the activity of perioperative ChIO considering HLA class I defects.

RESULTS

HLA-DEF tumors comprised 41.7% of analyzed tumors and showed a desert-like microenvironment at baseline, with lower PD-L1 levels and reduced immune infiltrate. However, perioperative ChIO induced similar complete pathological response (CPR) rates in both HLA-DEF and PRO tumors (50% and 60% respectively, p=0.670), as well as 3-year survival rates: Progression-free survival (PFS) and overall survival (OS) of 70% (95% CI 32.9% to 89.2%) for HLA-DEF, and PFS 71.4% (95% CI 40.6% to 88.2%) and OS 92.9% (95% CI 59.1% to 99.0%) for HLA-PRO (log-rank PFS p=0.909, OS p=0.137). Proof-of-concept ST analysis of a CPR HLA-DEF tumor after ChIO showed a strong immune response with tertiary lymphoid structures (TLS), CD4+T cells with HLA class II colocalization, and activated CD8+T cells.

CONCLUSIONS

Our findings highlight the activity of perioperative ChIO, and the potential role of TLS and T-cell immune response, in NSCLC HLA-DEF tumors.

Epidermal growth factor receptor/mitogen-activated kinase inhibitor treatment induces a distinct inflammatory hair follicle response that includes collapse of immune privilege

BACKGROUND

Inhibitors of epidermal growth factor receptor (EGFRi) or mitogen-activated kinase (MEKi) induce a folliculitis in 75-90% of patients, the pathobiology of which remains insufficiently understood.

OBJECTIVES

To characterize changes in the skin immune status and global transcriptional profile of patients treated with EGFRi; to investigate whether EGFRi affects the hair follicle's (HF) immune privilege (IP); and to identify early proinflammatory signals induced by EGFRi/MEKi in human scalp HFs ex vivo.

METHODS

Scalp biopsies were taken from patients exhibiting folliculitis treated long term with EGFRi ('chronic EGFRi' group, n = 9) vs. healthy scalp skin (n = 9) and patients prior to commencing EGFRi treatment and after 2 weeks of EGFRi therapy ('acute EGFRi' group, n = 5). Healthy organ-cultured scalp HFs were exposed to an EGFRi (erlotinib, n = 5) or a MEKi (cobimetinib, n = 5). Samples were assessed by quantitative immunohistomorphometry, RNA sequencing (RNAseq) and in situ hybridization.

RESULTS

The 'chronic EGFRi' group showed CD8+ T-cell infiltration of the bulge alongside a partial collapse of the HF's IP, evidenced by upregulated major histocompatibility complex (MHC) class I, β2-microglobulin (B2 M) and MHC class II, and decreased transforming growth factor-β1 protein expression. Healthy HFs treated with EGFRi/MEKi ex vivo also showed partial HF IP collapse and increased transcription of human leucocyte antigen (HLA)-A, HLA-DR and B2 M transcripts. RNAseq analysis showed increased transcription of chemokines (CXCL1, CXCL13, CCL18, CCL3, CCL7) and interleukin (IL)-26 in biopsies from the 'chronic EGFRi' cohort, as well as increased IL-33 and decreased IL-37 expression in HF biopsies from the 'acute EGFRi' group and in organ-cultured HFs.

CONCLUSIONS

The data show that EGFRi/MEKi compromise the physiological IP of human scalp HFs and suggest that future clinical management of EGFRi/MEKi-induced folliculitis requires HF IP protection and inhibition of IL-33.

Impact of immune-related adverse events on survival among patients with head-and-neck squamous cell carcinoma

Aim: Immune-checkpoint inhibitors (ICIs) have revolutionized treatment of metastatic head and neck squamous cell carcinomas (HNSCCs). Our goal was to assess for an association between immune-related adverse events (irAEs) and clinical outcomes for patients on ICIs.Methods: We analyzed a cohort of 110 HNSCC patients who received ICI therapy at the University of Virginia.Results: On review, 48% of our patients experienced an irAE with the most common events being hypothyroidism (30%), dermatitis (14%) and hepatitis (11%). Women were more likely to experience irAEs. Treatment interruption/discontinuation occurred in 43% patients with irAEs. Development of irAEs was associated with superior objective response rate (68 vs. 39%, p = 0.009), with a greater rate of CR (17 vs. 5%) and PR (32 vs. 16%). Twelve patients underwent ICI re-treatment following irAE, with 17% attaining a complete disease response, 25% attaining a partial response, 33% achieving stable disease and 25% experiencing disease progression with ICI resumption.Conclusion: Development of irAE was associated with superior objective response rate, with a greater rate of CR and PR. ICI re-treatment following irAE was feasible in a significant proportion of patients and can be attempted in carefully selected patients, given the dearth of second-line therapies for these patients.

PD-L1+ Lymphocytes Are Associated with CD4+, Foxp3+CD4+, IL17+CD4+ T Cells and Subtypes of Macrophages in Resected Early-Stage Non-Small Cell Lung Cancer

The non-canonical PD-L1 pathway revealed that programmed-death ligand 1 (PD-L1) expression in immune cells also plays a crucial role in immune response. Moreover, immune cell distribution in a tumour microenvironment (TME) is pivotal for tumour genesis. However, the results remain controversial and further research is needed. Distribution of PD-L1-positive (PD-L1+) tumour-infiltrating lymphocytes in the context of TME was assessed in 72 archival I-III stage surgically resected NSCLC tumour specimens. Predominant PD-L1+ lymphocyte distribution in the tumour stroma, compared to islets, was found (p = 0.01). Higher PD-L1+ lymphocyte infiltration was detected in smokers due to their predominance in the stroma. High PD-L1+ lymphocyte infiltration in tumour stroma was more common in tumours with higher CD4+ T cell infiltration in islets and stroma, Foxp3+CD4+ T cell infiltration in islets and lover M1 macrophage infiltration in the stroma (p = 0.034, p = 0.034, p = 0.005 and p = 0.034 respectively). Meanwhile, high PD-L1+ lymphocyte infiltration in islets was predominantly found in tumours with high levels of IL-17A+CD4+ T cells in islets and Foxp3+CD4+ T cells in islets and stroma (p = 0.032, p = 0.009 and p = 0.034, respectively). Significant correlations between PD-L1+ lymphocytes and tumour-infiltrating CD4+, Foxp3+CD4+, IL-17A+CD4+ T cells and M2 macrophages were found. An analysis of the tumour-immune phenotype revealed a significant association between PD-L1 expression and IL17+CD4+ and Foxp3+CD4+ immune phenotypes. PD-L1+ lymphocytes are associated with the distribution of CD4+, Foxp3+CD4+, IL17A+CD4+ T cells, M1 and M2 macrophages in TME of resected NSCLC.

Epidemiology and tumor microenvironment of ocular surface and orbital tumors on growth and malignant transformation

The ocular surface and orbit constitute unique microenvironments in the human body. Current advances in molecular research have deepened our understanding of tumor development in these regions. Tumors exhibit greater heterogeneity compared to normal tissues, as revealed by pathological and histological examinations. The tumor microenvironment (TME) plays a crucial role in the proliferation and progression of cancer cells. Factors from the external environment or the body's own inflammation and microcirculation interact within the TME, maintaining a delicate balance. Disruption of this balance, through uncontrolled signal pathway activation, can transform normal or benign tissues into malignant ones. In recent years, various systemic immunotherapies have been developed for cancer treatment. This study reviews the epidemiology of ocular surface and orbital tumors include squamous cell carcinoma, basal cell carcinoma, sebaceous carcinoma and lymphoma in conjunction with their occurrence, growth, and underlying mechanisms. We propose that by examining clinical histopathological images, we can identify specific and shared microscopic features of tumors. By collecting, classifying, and analyzing data from these clinical histopathological images, we can pinpoint independent diagnostic factors characteristic of tumors. We hope this study provides a basis for future exploration of the mechanisms underlying different ocular diseases.

Cancer cell-specific PD-L1 expression is a predictor of poor outcome in patients with locally advanced oral cavity squamous cell carcinoma

BACKGROUND

Locally advanced oral cavity squamous cell carcinoma (OCSCC) presents a significant clinical challenge despite being partially responsive to standard treatment modalities. This study investigates the prognostic implications of programmed death-ligand 1 (PD-L1) expression in these tumors, focusing on its association with treatment outcomes and the immune microenvironment.

METHODS

We assessed tumor-infiltrating lymphocytes (TILs) in 132 patients with OCSCC to evaluate their impact on survival. Multiplex immunohistochemistry staining for CD3, CD68, CD11c, PD-L1, and P40 was used to explore correlations with clinical outcomes in patients with early-stage (n=22) and locally advanced (n=36) OCSCC. These initial findings were validated through differential gene expression analysis, gene set enrichment, and immune cell deconvolution in a The Cancer Genome Atlas cohort of 163 locally advanced OCSCC tumors. Additionally, single-cell RNA sequencing (scRNA-seq) on a smaller cohort (n=10) further characterized the PD-L1hi or PD-L1lo cancer cells in these tumors.

RESULTS

Elevated PD-L1 expression was associated with poor outcomes in patients with locally advanced OCSCC undergoing standard adjuvant therapy, irrespective of "hot" or "cold" classification based on TILs assessment. PD-L1hi tumors exhibited an active immune response phenotype, enriched with M1 macrophages, CD8+ T cells and T regulatory cells in the tumor microenvironment. Notably, the negative impact of PD-L1 expression on outcomes was primarily attributed to its expression by cancer cells, rather than immune cells. Furthermore, scRNA-seq revealed that immune interactions were not essential for PD-L1 upregulation in cancer cells, instead, complex regulatory networks were involved. Additionally, PD-L1lo locally advanced tumors exhibited more complex pathway enrichment and diverse T-cell populations compared with those in the early-stage.

CONCLUSION

Our findings underscore the prognostic significance of PD-L1 expression in locally advanced OCSCC, and unveil the complex interplay between PD-L1 expression, immune responses, and molecular pathways in the tumor microenvironment. This study provides insights that may inform future therapeutic strategies, including the possibility of tailored immunotherapeutic approaches for patients with PD-L1hi locally advanced OCSCC.

Plasma Extracellular Vesicles Derived from Pediatric COVID-19 Patients Modulate Monocyte and T Cell Immune Responses Based on Disease Severity

BACKGROUND

The COVID-19 pandemic has caused significant morbidity and mortality globally. The role of plasma-derived extracellular vesicles (EVs) in pediatric COVID-19 patients remains unclear.

METHODS

We isolated EVs from healthy controls (n = 13) and pediatric COVID-19 patients (n = 104) with varying severity during acute and convalescent phases using serial ultracentrifugation. EV effects on healthy PBMCs, naïve CD4+ T cells, and monocytes were assessed through in vitro assays, flow cytometry, and ELISA.

RESULTS

Our findings indicate that COVID-19 severity correlates with diverse immune responses. Severe acute cases exhibited increased cytokine levels, decreased IFNγ levels, and lower CD4+ T cell and monocyte counts, suggesting immunosuppression. EVs from severe acute patients stimulated healthy cells to express higher PDL1, increased Th2 and Treg cells, reduced IFNγ secretion, and altered Th1/Th17 ratios. Patient-derived EVs significantly reduced proinflammatory cytokine production by monocytes (p < .001 for mild, p = .0025 for severe cases) and decreased CD4+ T cell (p = .043) and monocyte (p = .033) populations in stimulated healthy PBMCs.

CONCLUSION

This study reveals the complex relationship between immunological responses and EV-mediated effects, emphasizing the impact of COVID-19 severity. We highlight the potential role of plasma-derived EVs in early-stage immunosuppression in severe COVID-19 patients.

Tumor-associated macrophages: A sentinel of innate immune system in tumor microenvironment gone haywire

The tumor microenvironment (TME) is a critical determinant in the initiation, progression, and treatment outcomes of various cancers. Comprising of cancer-associated fibroblasts (CAF), immune cells, blood vessels, and signaling molecules, the TME is often likened to the soil supporting the seed (tumor). Among its constituents, tumor-associated macrophages (TAMs) play a pivotal role, exhibiting a dual nature as both promoters and inhibitors of tumor growth. This review explores the intricate relationship between TAMs and the TME, emphasizing their diverse functions, from phagocytosis and tissue repair to modulating immune responses. The plasticity of TAMs is highlighted, showcasing their ability to adopt either protumorigenic or anti-tumorigenic phenotypes based on environmental cues. In the context of cancer, TAMs' pro-tumorigenic activities include promoting angiogenesis, inhibiting immune responses, and fostering metastasis. The manuscript delves into therapeutic strategies targeting TAMs, emphasizing the challenges faced in depleting or inhibiting TAMs due to their multifaceted roles. The focus shifts towards reprogramming TAMs to an anti-tumorigenic M1-like phenotype, exploring interventions such as interferons, immune checkpoint inhibitors, and small molecule modulators. Noteworthy advancements include the use of CSF1R inhibitors, CD40 agonists, and CD47 blockade, demonstrating promising results in preclinical and clinical settings. A significant section is dedicated to Chimeric Antigen Receptor (CAR) technology in macrophages (CAR-M cells). While CAR-T cells have shown success in hematological malignancies, their efficacy in solid tumors has been limited. CAR-M cells, engineered to infiltrate solid tumors, are presented as a potential breakthrough, with a focus on their development, challenges, and promising outcomes. The manuscript concludes with the exploration of third-generation CAR-M technology, offering insight into in-vivo reprogramming and nonviral vector approaches. In conclusion, understanding the complex and dynamic role of TAMs in cancer is crucial for developing effective therapeutic strategies. While early-stage TAM-targeted therapies show promise, further extensive research and larger clinical trials are warranted to optimize their targeting and improve overall cancer treatment outcomes.

Clinical prognosticators and targets in the immune microenvironment of intrahepatic cholangiocarcinoma

Background

Intrahepatic cholangiocarcinoma (ICC) is a disease with poor prognosis and limited therapeutic options. We investigated the tumor immune microenvironment (TIME) to identify predictors of disease outcome and to explore targets for therapeutic modulation.

Methods

Liver tissue samples were collected during 2008-2019 from patients (n = 139) diagnosed with ICC who underwent curative intent surgery without neoadjuvant chemotherapy. Samples from the discovery cohort (n = 86) were immunohistochemically analyzed on tissue microarrays (TMAs) for the expression of CD68, CD3, CD4, CD8, Foxp3, PD-L1, STAT1, and p-STAT1 in tumor core and stroma areas. Results were digitally analyzed using QuPath software and correlated with clinicopathological characteristics. For validation of TIME-related biomarkers, we performed multiplex imaging mass cytometry (IMC) in a validation cohort (n = 53).

Results

CD68+ cells were the predominant immune cell type in the TIME of ICC. CD4+high T cell density correlated with better overall survival (OS). Prediction modeling together with validation cohort confirmed relevance of CD4+ cells, PD-L1 expression by immune cells in the stroma and N-stage on overall disease outcome. In turn, IMC analyses revealed that silent CD3+CD4+ clusters inversely impacted survival. Among annotated immune cell clusters, PD-L1 was most relevantly expressed by CD4+FoxP3+ cells. A subset of tumors with high density of immune cells ("hot" cluster) correlated with PD-L1 expression and could identify a group of candidates for immune checkpoint inhibition (ICI). Ultimately, higher levels of STAT1 expression were associated with higher lymphocyte infiltration and PD-L1 expression.

Conclusions

These results highlight the importance of CD4+ T cells in immune response against ICC. Secondly, a subset of tumors with "hot" TIME represents potential candidates for ICI, while stimulation of STAT1 pathway could be a potential target to turn "cold" into "hot" TIME in ICC.

Research progress and challenges of the PD-1/PD-L1 axis in gliomas

The emergence of programmed death-1 (PD-1) and programmed death ligand 1 (PD-L1) immunosuppressants provides new therapeutic directions for various advanced malignant cancers. At present, PD-1/PD-L1 immunosuppressants have made significant progress in clinical trials of some gliomas, but PD-1/PD-L1 inhibitors have not yet shown convincing clinical efficacy in gliomas. This article summarizes the research progress of the PD-1 /PD-L1 pathway in gliomas through the following three aspects. It mainly includes the complex expression levels and regulatory mechanisms of PD-1/PD-L1 in the glioma microenvironment, the immune infiltration in glioma immunosuppressive microenvironment, and research progress on the application of PD-1/PD-L1 immunosuppressants in clinical treatment trials for gliomas. This will help to understand the current treatment progress and future research directions better.

Therapeutic and immunomodulatory effects of Bojungikki-tang on cancer: a scoping review

BACKGROUND

Cancer remains a major global health concern, with conventional treatments often limited by side effects and resistance. Bojungikki-tang (BJIKT), a traditional herbal formula, has shown promise in alleviating cancer-related symptoms and enhancing anti-cancer effects when combined with conventional treatments. As immune checkpoint inhibitors (ICIs) have become the standard for cancer treatment, a combination of BJIKT and ICIs may exhibit immune-mediated anti-cancer effects. This review aims to summarize the recent evidence on BJIKT use in cancer treatment, investigate its immunomodulatory effects, and identify research gaps.

METHODS

This review was conducted and reported following the Arksey and O'Malley framework and the Preferred Reporting Items for Systematic Reviews and Meta-Analysis Scoping Review. A comprehensive search of six electronic databases was conducted, and studies published between 2013 and 2022 were identified. Reports on oral administration of BJIKT to patients with cancer were included and analyzed by two reviewers. The extracted data were synthesized using descriptive reporting and meta-analysis.

RESULTS

Overall, 56 studies met the inclusion criteria: 36 human studies, 14 experimental studies, and 6 reviews on clinical and preclinical investigations. The use of BJIKT in restoring immune function and improving fatigue, cancer-related fever, and quality of life after chemotherapy has been reported in clinical studies. The different medication forms of BJIKT included decoction, extract granules, pills, and water extract. The meta-analysis revealed a significantly higher Karnofsky Performance Scale score in the BJIKT plus chemotherapy group than in the chemotherapy alone group. Preclinical studies have demonstrated that BJIKT has anti-cancer effects, enhances gastrointestinal function and immunomodulatory effects, and supports favorable chemotherapy outcomes.

CONCLUSION

In recent clinical research on BJIKT, its impact on fatigue, quality of life, and alleviating cancer-related fever has mostly been examined. The direct anti-cancer activities and immunomodulatory mechanisms of BJIKT have been reported in preclinical studies; however, clinical research on BJIKT-induced enhancement of immune function is lacking. Further research on the efficacy and safety of ICI combined with BJIKT and the association of immunomarker changes with clinical outcomes is required to precisely identify the effect of BJIKT on immune system modulation.

Prognostic value of tumor-infiltrating lymphocytes and PD-L1 expression in esophageal squamous cell carcinoma

BACKGROUND

Tumor cells (TC) participate in tumor progression by altering the immune responses in the tumor microenvironment. However, the clinical relevance and prognostic effect of PD-L1 expression and tumor-infiltrating lymphocytes (TILs) in esophageal squamous cell carcinoma (ESCC) are unknown. The purpose of this study was to investigate the interactions and clinical significance of PD-L1 expression and TILs in ESCC.

METHODS

Tissue specimens were collected from 126 patients with ESCC who underwent curative esophagectomy. Immunohistochemical analysis and multiplex immunofluorescence for CD4, CD8, CD25, FOXP3, and PD-L1 in the tumor were used to identify multiple tumor-infiltrating immune cells (TIIC), Tregs, and TC.

RESULTS

PD-L1 was expressed in tumor cells (PD-L1 TC). PD-L1 TIIC and PD-L1 TC affected the biological behavior of TC. The positive expression rate of PD-L1 TC and CD8+ TILs was 27.8% (35/126) and 31.7% (40/126), respectively. Kaplan-Meier analysis showed that overall survival (OS) was significantly associated with decreased CD8+ TILs and PD-L1 TC-positive expression, which promote ESCC progression and metastasis.

CONCLUSION

Tumor depth, CD8, and PD-L1 TC were independent prognostic factors in ESCC, and a predictive nomogram with these three risk factors improved the accuracy of predicting OS in patients with ESCC after surgical resection. The conjoint analysis of multiple immune-related factors is beneficial for stratifying patient survival risk.

Mutational Features and Tumor Microenvironment Alterations in High-Grade Appendiceal Cancers Treated With Iterative Hyperthermic Intraperitoneal Chemotherapy

PURPOSE

High-grade appendiceal adenocarcinomas (HGAA) with peritoneal metastases (PMs) are associated with poor survival. Hyperthermic intraperitoneal chemotherapy (HIPEC) is a novel treatment approach for unresectable HGAA-PM. However, its influence on immunogenomic profiles has not yet been fully explored.

MATERIALS AND METHODS

We obtained 79 samples of metastatic peritoneal tumor deposits from patients diagnosed with HGAA and performed whole-exome sequencing, RNA sequencing, and immunoprofiling before and after HIPEC. Tumor biopsies were subjected to immunogenomic profiling to detect mutational signatures and immune populations associated with oncologic outcomes.

RESULTS

Fifteen patients with HGAA-PMs were included in the study. The median progression-free survival (PFS) was 6.7 months (2.7-25.3) and the median overall survival was 11.4 months (4.7-42). Mucin-associated genes (MUC16, MUC3A, and MUC5AC) and titin (TTN) had the highest mutation frequencies. Mutational signatures such as single-base substitution 29 and doublet-base substitution 11 were present in >50% of single-base and double-base mutations. Higher PD-L1 coexpression on CD8+ T cells demonstrated a higher PFS both intratumorally (P = .019) and at the margin (P = .025).

CONCLUSION

HIPEC-associated mutational signatures were identified in HGAA-PMs. Elevated PD-L1+ cytotoxic T-cell populations after HIPEC had better PFS, offering valuable insights for prognostication in the context of HIPEC treatment.

IL-21- and CXCL9-engineered GPC3-specific CAR-T cells combined with PD-1 blockade enhance cytotoxic activities against hepatocellular carcinoma

The application of CAR-T cells in solid tumors poses several challenges, including poor T cell homing ability, limited infiltration of T cells and an immunosuppressive tumor environment. In this study, we developed a novel approach to address these obstacles by designing GPC3-specific CAR-T cell that co-express IL-21 and CXCL9 (21 × 9 GPC3 CAR-T cells) and blocking the PD-1 expression on it. The proliferation, cell phenotype, cytokine secretion and cell migration of indicated CAR-T cells were evaluated in vitro. The cytotoxic activities of genetically engineered CAR-T cells were accessed in vitro and in vivo. Compared to conventional GPC3 CAR-T cells, the 21 × 9 GPC3 CAR-T cells demonstrated superior proliferation, cytokine secretion and chemotaxis capabilities in vitro. Furthermore, when combined with PD-1 blockade, the 21 × 9 GPC3 CAR-T cells exhibited enhanced proliferation, cytokine secretion and enrichment of effector T cells such as CTL, NKT and TEM cells. In xenograft tumor models, the PD-1 blocked 21 × 9 GPC3 CAR-T cells effectively suppressed HCC xenograft growth and increased T cell infiltration. Overall, our study successfully generated GPC3 CAR-T cells expressing both IL-21 and CXCL9, demonstrated that combining PD-1 blockade can further enhance CAR-T cell function by promoting proliferation, cytokine secretion, chemotaxis and antitumor activity. These findings present a hopeful and potentially effective strategy for GPC3-positive HCC patients.

Tertiary lymphoid structure-related immune infiltrates in NSCLC tumor lesions correlate with low tumor-reactivity of TIL products

Adoptive transfer of tumor infiltrating lymphocytes (TIL therapy) has proven highly effective for treating solid cancers, including non-small cell lung cancer (NSCLC). However, not all patients benefit from this therapy for yet unknown reasons. Defining markers that correlate with high tumor-reactivity of the autologous TIL products is thus key for achieving better tailored immunotherapies. We questioned whether the composition of immune cell infiltrates correlated with the tumor-reactivity of expanded TIL products. Unbiased flow cytometry analysis of immune cell infiltrates of 26 early-stage and 20 late-stage NSCLC tumor lesions was used for correlations with the T cell differentiation and activation status, and with the expansion rate and anti-tumor response of generated TIL products. The composition of tumor immune infiltrates was highly variable between patients. Spearman's Rank Correlation revealed that high B cell infiltration negatively correlated with the tumor-reactivity of the patient's expanded TIL products, as defined by cytokine production upon exposure to autologous tumor digest. In-depth analysis revealed that tumor lesions with high B cell infiltrates contained tertiary lymphoid structure (TLS)-related immune infiltrates, including BCL6+ antibody-secreting B cells, IgD+BCL6+ B cells and CXCR5+BLC6+ CD4+ T cells, and higher percentages of naïve CD8+ T cells. In conclusion, the composition of immune cell infiltrates in NSCLC tumors associates with the functionality of the expanded TIL product. Our findings may thus help improve patient selection for TIL therapy.

Lymphatic system regulation of anti-cancer immunity and metastasis

Cancer dissemination to lymph nodes (LN) is associated with a worse prognosis, increased incidence of distant metastases and reduced response to therapy. The LN microenvironment puts selective pressure on cancer cells, creating cells that can survive in LN as well as providing survival advantages for distant metastatic spread. Additionally, the presence of cancer cells leads to an immunosuppressive LN microenvironment, favoring the evasion of anti-cancer immune surveillance. However, recent studies have also characterized previously unrecognized roles for tumor-draining lymph nodes (TDLNs) in cancer immunotherapy response, including acting as a reservoir for pre-exhausted CD8+ T cells and stem-like CD8+ T cells. In this review, we will discuss the spread of cancer cells through the lymphatic system, the roles of TDLNs in metastasis and anti-cancer immune responses, and the therapeutic opportunities and challenges in targeting LN metastasis.

Efficacy of programmed cell death 1 inhibitor maintenance after chimeric antigen receptor T cells in patients with relapsed/refractory B-cell non-Hodgkin-lymphoma

INTRODUCTION

Chimeric antigen receptor (CAR)-T cells obtained long-term durability in about 30% to 40% of relapsed/refractory (r/r) B-cell non-Hodgkin lymphoma (B-NHL). Maintenance therapy after CAR-T is necessary, and PD1 inhibitor is one of the important maintenance therapy options.

METHODS

A total of 173 r/r B-NHL patients treated with PD1 inhibitor maintenance following CD19/22 CAR-T therapy alone or combined with autologous hematopoietic stem cell transplantation (ASCT) from March 2019 to July 2022 were assessed for eligibility for two trials. There were 81 patients on PD1 inhibitor maintenance therapy.

RESULTS

In the CD19/22 CAR-T therapy trial, the PD1 inhibitor maintenance group indicated superior objective response rate (ORR) (82.9% vs 60%; P = 0.04) and 2-year progression-free survival (PFS) (59.8% vs 21.3%; P = 0.001) than the non-maintenance group. The estimated 2-year overall survival (OS) was comparable in the two groups (60.1% vs 45.1%; P = 0.112). No difference was observed in the peak expansion levels of CD19 CAR-T and CD22 CAR-T between the two groups. The persistence time of CD19 and CD22 CAR-T in the PD1 inhibitor maintenance group was longer than that in the non-maintenance group. In the CD19/22 CAR-T therapy combined with ASCT trial, no significant differences in ORR (81.4% vs 84.8%; P = 0.67), 2-year PFS (72.3% vs 74.9%; P = 0.73), and 2-year OS (84.1% vs 80.7%; P = 0.79) were observed between non-maintenance and PD1 inhibitor maintenance therapy groups. The peak expansion levels and duration of CD19 and CD22 CAR-T were not statistically different between the two groups. During maintenance treatment with PD1 inhibitor, all adverse events were manageable. In the multivariable analyses, type and R3m were independent predictive factors influencing the OS of r/r B-NHL with PD1 inhibitor maintenance after CAR-T therapy.

CONCLUSION

PD1 inhibitor maintenance following CD19/22 CAR-T therapy obtained superior response and survival in r/r B-NHL, but not in the trial of CD19/22 CAR-T cell therapy combined with ASCT.

New expression of PD-L1 on activated CD4+ T cells opens up new opportunities for cell interactions and signaling

Surface expression of programmed death-ligand 1 (PD-L1) is mainly observed on antigen presenting cells (APC) such as monocytes or dendritic cells (DCs). Our results showing a high expression of PD-L1 on human naïve CD4+ effector T-cells (TEFFs) and CD4+ regulatory T cells (TREGs) after activation with human DCs, allow us to propose a new role for PD-L1 and its ligands and their potential impact on new signaling pathways. Indeed, expression of PD-L1 on activated CD4+T cells could allow cis interaction with its ligands such as PD-1 and CD80, thus disrupting interactions with other signaling receptors, such as cytotoxic T-lymphocyte antigen-4 (CTLA-4) or CD28, which interact with CD80. The ability to compete with hypothetical configuration modifications that may cause a change in affinity/avidity for the trans and cis interactions between these proteins expressed on T cells and/or DCs is discussed. As the study of cancer is strongly influenced by the role of the PD-L1/PD-1 pathway and CD4+T cells, new interactions, cis and/or trans, between TEFFs, TREGs and tumor cells are also proposed. The presence of PD-L1 on activated CD4+ T cells could influence the quality of the cytotoxic T lymphocyte response during priming to provide other help signals.

PD-L1 promotes oncolytic virus infection via a metabolic shift that inhibits the type I IFN pathway

While conventional wisdom initially postulated that PD-L1 serves as the inert ligand for PD-1, an emerging body of literature suggests that PD-L1 has cell-intrinsic functions in immune and cancer cells. In line with these studies, here we show that engagement of PD-L1 via cellular ligands or agonistic antibodies, including those used in the clinic, potently inhibits the type I interferon pathway in cancer cells. Hampered type I interferon responses in PD-L1-expressing cancer cells resulted in enhanced efficacy of oncolytic viruses in vitro and in vivo. Consistently, PD-L1 expression marked tumor explants from cancer patients that were best infected by oncolytic viruses. Mechanistically, PD-L1 promoted a metabolic shift characterized by enhanced glycolysis rate that resulted in increased lactate production. In turn, lactate inhibited type I IFN responses. In addition to adding mechanistic insight into PD-L1 intrinsic function, our results will also help guide the numerous ongoing efforts to combine PD-L1 antibodies with oncolytic virotherapy in clinical trials.

A combination of 5-azacytidine and nivolumab is a potentially effective rescue therapy in relapsed/refractory AITL

Introduction

Angioimmunoblastic T-cell lymphoma (AITL) is a peripheral T-cell lymphoma characterized by a T follicular helper cell phenotype expressing PD-1 (programmed cell death-1). AITL exhibits a poor response to conventional chemotherapy, with a median 5-year overall survival of 44% and a progression-free survival of 32%. Relapse is common, resulting in a median overall survival of 6 months. Recurrent mutations are detected in genes regulating DNA methylation, including TET2, DNMT3A, and IDH2 variants, along with the prevalent RHOA G17V mutation. In this context, patients treated with the hypomethylating agent 5-azacytidine achieved overall response and complete response rates of 75% and 41%, respectively. We hypothesized that targeted therapies combining anti-PD-1 checkpoint blockers with hypomethylating agents could be efficient in AITL patients and less toxic than standard chemotherapy.

Methods

Here, we report the efficacy of a regimen combining 5-azacytidine and nivolumab in nine relapsed or refractory AITL patients.

Results

This regimen was well-tolerated, especially in elderly patients. The overall response rate was 78%, including four partial responses (44%) and three complete responses (33%). Allogeneic hematopoietic stem cell transplantation was performed in two patients who reached complete response.

Discussion

These preliminary favorable results may serve as a basis for further investigation in prospective studies.

PD-L1 has a heterogeneous and dynamic expression in gastric cancer with implications for immunoPET

Introduction

This study aimed to investigate the dynamics of programmed death-ligand 1 (PD-L1) expression, spatial heterogeneity, and binding affinity of FDA-approved anti-PD-L1 antibodies (avelumab and atezolizumab) in gastric cancer. Additionally, we determined how PD-L1 glycosylation impacts antibody accumulation in gastric cancer cells.

Methods

Dynamic PD-L1 expression was examined in NCIN87 gastric cancer cells. Comparative binding studies of avelumab and atezolizumab were conducted in gastric cancer models, both in vitro and in vivo. Antibody uptake in tumors was visualized through positron emission tomography (PET) imaging. PD-L1 glycosylation status was determined via Western blot analyses before and after PNGase F treatment.

Results

Consistent findings revealed time-dependent PD-L1 induction in NCIN87 gastric cancer cells and spatial heterogeneity in tumors, as shown by PET imaging and immunofluorescence. Avelumab displayed superior binding affinity to NCIN87 cells compared to atezolizumab, confirmed by in vivo PET imaging and ex vivo biodistribution analyses. Notably, PD-L1 glycosylation at approximately 50 kDa was observed, with PNGase F treatment inducing a shift to 35 kDa in molecular weight. Tissue samples from patient-derived xenografts (PDXs) validated the presence of both glycosylated and deglycosylated PD-L1 (degPD-L1) forms in gastric cancer. Immunofluorescence microscopy and binding assays demonstrated enhanced avelumab binding post-deglycosylation.

Discussion

This study provides an understanding of dynamic and spatially heterogeneous PD-L1 expression in gastric cancer. Anti-PD-L1 immunoPET was able to visualize gastric tumors, and PD-L1 glycosylation has significant implications for antibody recognition. These insights contribute to demonstrating the complexities of PD-L1 in gastric cancer, holding relevance for refining PD-L1 imaging-based approaches.

Antitumor efficacy and potential mechanism of FAP-targeted radioligand therapy combined with immune checkpoint blockade

Radiotherapy combined with immune checkpoint blockade holds great promise for synergistic antitumor efficacy. Targeted radionuclide therapy delivers radiation directly to tumor sites. LNC1004 is a fibroblast activation protein (FAP)-targeting radiopharmaceutical, conjugated with the albumin binder Evans Blue, which has demonstrated enhanced tumor uptake and retention in previous preclinical and clinical studies. Herein, we demonstrate that 68Ga/177Lu-labeled LNC1004 exhibits increased uptake and prolonged retention in MC38/NIH3T3-FAP and CT26/NIH3T3-FAP tumor xenografts. Radionuclide therapy with 177Lu-LNC1004 induced a transient upregulation of PD-L1 expression in tumor cells. The combination of 177Lu-LNC1004 and anti-PD-L1 immunotherapy led to complete eradication of all tumors in MC38/NIH3T3-FAP tumor-bearing mice, with mice showing 100% tumor rejection upon rechallenge. Immunohistochemistry, single-cell RNA sequencing (scRNA-seq), and TCR sequencing revealed that combination therapy reprogrammed the tumor microenvironment in mice to foster antitumor immunity by suppressing malignant progression and increasing cell-to-cell communication, CD8+ T-cell activation and expansion, M1 macrophage counts, antitumor activity of neutrophils, and T-cell receptor diversity. A preliminary clinical study demonstrated that 177Lu-LNC1004 was well-tolerated and effective in patients with refractory cancers. Further, scRNA-seq of peripheral blood mononuclear cells underscored the importance of addressing immune evasion through immune checkpoint blockade treatment. This was emphasized by the observed increase in antigen processing and presentation juxtaposed with T cell inactivation. In conclusion, our data supported the efficacy of immunotherapy combined with 177Lu-LNC1004 for cancer patients with FAP-positive tumors.