Host expression of PD-L1 determines efficacy of PD-L1 pathway blockade-mediated tumor regression

PD-L1 targeted antibody-polymer-Epirubicin conjugate prolongs survival in a preclinical murine model of advanced ovarian cancer

Following successful design of polymer enhanced rituximab-epirubicin (EPI) conjugates targeted to non-Hodgkin lymphoma (Zhang et al. 2017), we developed U6244-051 that consists of anti-PD-L1 antibody (αPD-L1) and semitelechelic N-(2-hydroxypropyl)methacrylamide (HPMA) copolymer-epirubicin (EPI) conjugates (ST-P-EPI); the latter is attached to αPD-L1 via Cu-free azide/alkyne cycloaddition. This new polymer-enhanced antibody-drug conjugate (pADC) not only exhibits a high drug-to-antibody ratio (DAR ∼ 30-40) but also integrates immune checkpoint blockade with long-lasting immunogenic anticancer chemotherapy, providing an innovative chemo-immuno combination modality. The biological properties of U6244-051 were evaluated using ID8-Luc murine ovarian cancer cells in vitro and in vivo. In vitro, U6244-051 treatment induced immunomodulatory changes, including upregulation of calreticulin, PD-L1, and MHC I, suggesting enhanced tumor cell visibility to the immune system. In vivo efficacy was assessed in a syngeneic murine model (C57BL/6J mice inoculated with 5 × 106 ID8-Luc cells/mouse). U6244-051 treatment resulted in 100 % survival at day 100, despite initiation at an advanced disease stage. Treatment modulated the tumor immune microenvironment by reducing immunosuppressive populations (TAMs and MDSCs) and enhancing T cell recruitment and activation. A decrease in PD-L1 expression and upregulation of MHC I correlated with enhanced immune-mediated tumor clearance. Additionally, reduced Treg levels and increased CD8+ T cell activation contributed to a more effective antitumor response. Repeated dosing amplified immunomodulatory effects, leading to durable immunity. These results highlight U6244-051 as a next-generation pADC with high translational potential, offering enhanced efficacy and reduced on-target, off-tumor toxicity.

STING-activable immunomodulatory bio-glue for multiple postsurgical management

In addition to the robust adhesive properties, there is a pressing demand for ideal adhesives in tumor surgery that possess anti-tumor therapeutic effects. In this study, we introduce BSA-MnO2-GP@Ca-Y (BMGY) bio-glue by integrating bovine serum albumin (BSA)-MnO2, genipin (GP), and Ca-Y zeolite. Ca-Y zeolite exhibits the thrombin activity for hemostasis, while the cross-linking of BSA, GP, and skin tissue induces wound adherence upon laser irradiation for normalized skin structure within nine days. The heat generated during the "photothermal suture" process ablates residual tumor cells and produces antigen fragments, which are internalized by antigen presenting cells. The released Mn ions subsequently activate the cGAS-STING pathway, enhancing immunogenicity. Consequently, tumor-infiltrating p-TBK1 and interferon-β levels are significantly increased, ensuring robust anti-tumor immunity following BMGY treatment. Thus, BMGY bio-glue achieves hemostasis, wound bonding, ablation of residual tumor cells, and tumor recurrence inhibition, simultaneously. Beyond Ca-Y zeolite, BSA-MnO2-GP serves as a versatile platform for loading other drugs or active species to boost therapeutic efficacy. Therefore, we present a successful bio-glue paradigm with significant translational potential for various postsurgical management applications.

The tumor microenvironment's role in the response to immune checkpoint blockade

Beyond cancer cells, the tumor microenvironment (TME) includes cells of the innate and adaptive immune systems but also non-immune cells, such as fibroblasts and endothelial cells. Depending on the cues they receive, infiltrating myeloid cells, such as monocytes, macrophages, dendritic cells and neutrophils, perform immune stimulatory or suppressive functions by educating adaptive immune cells, thereby guiding their responses to cancer cells and cancer treatment, such as immune checkpoint blockade (ICB). The increasing understanding that anti-tumor immunity goes beyond T cells with improved functionality, and the unraveling of resistance mechanisms beyond T cell exhaustion, have renewed interest in non-T cell components of the TME to identify novel therapeutic targets and improve ICB responses. Here, we review immune and non-immune cellular components of the TME that regulate adaptive cell responses and their role in ICB response and resistance.

Spatial analysis identifies DC niches as predictors of pembrolizumab therapy in head and neck squamous cell cancer

Head and neck squamous cell carcinoma (HNSCC) shows variable response to anti-programmed cell death protein 1 (PD-1) therapy, which can be partially explained by a combined positive score (CPS) of tumor and immune cell expression of programmed death-ligand 1 (PD-L1) within the local tumor microenvironment (TME). To better define TME immune determinants associated with treatment efficacy, we conduct a study of n = 48 HNSCC tumors from patients prior to pembrolizumab therapy. Our investigation combines a rapid bioorthogonal multiplex staining method with computational analysis of whole-slide imaging to capture the single-cell spatial heterogeneity and complexity of the TME. Analyzing 6,316 fields of view (FOVs), we provide comprehensive PD-L1 phenotyping and cell proximity assays across the entirety of tissue sections. While none of the PD-L1 metrics adequately predict response, we find that the spatial organization of CCR7+ dendritic cells (DCs) in niches better predicts overall patient survival than CPS alone. This study highlights the importance of understanding the spatial context of immune networks for immunotherapy.

Tumor-associated macrophages remodel the suppressive tumor immune microenvironment and targeted therapy for immunotherapy

Despite the significant advances in the development of immune checkpoint inhibitors (ICI), primary and acquired ICI resistance remains the primary impediment to effective cancer immunotherapy. Residing in the tumor microenvironment (TME), tumor-associated macrophages (TAMs) play a pivotal role in tumor progression by regulating diverse signaling pathways. Notably, accumulating evidence has confirmed that TAMs interplay with various cellular components within the TME directly or indirectly to maintain the dynamic balance of the M1/M2 ratio and shape an immunosuppressive TME, consequently conferring immune evasion and immunotherapy tolerance. Detailed investigation of the communication network around TAMs could provide potential molecular targets and optimize ICI therapies. In this review, we systematically summarize the latest advances in understanding the origin and functional plasticity of TAMs, with a focus on the key signaling pathways driving macrophage polarization and the diverse stimuli that regulate this dynamic process. Moreover, we elaborate on the intricate interplay between TAMs and other cellular constituents within the TME, that is driving tumor initiation, progression and immune evasion, exploring novel targets for cancer immunotherapy. We further discuss current challenges and future research directions, emphasizing the need to decode TAM-TME interactions and translate preclinical findings into clinical breakthroughs. In conclusion, while TAM-targeted therapies hold significant promise for enhancing immunotherapy outcomes, addressing key challenges-such as TAM heterogeneity, context-dependent plasticity, and therapeutic resistance-remains critical to achieving optimal clinical efficacy.

STAT5 and STAT3 balance shapes dendritic cell function and tumour immunity

Immune checkpoint blockade (ICB) has transformed cancer therapy1,2. The efficacy of immunotherapy depends on dendritic cell-mediated tumour antigen presentation, T cell priming and activation3,4. However, the relationship between the key transcription factors in dendritic cells and ICB efficacy remains unknown. Here we found that ICB reprograms the interplay between the STAT3 and STAT5 transcriptional pathways in dendritic cells, thereby activating T cell immunity and enabling ICB efficacy. Mechanistically, STAT3 restrained the JAK2 and STAT5 transcriptional pathway, determining the fate of dendritic cell function. As STAT3 is often activated in the tumour microenvironment5, we developed two distinct PROTAC (proteolysis-targeting chimera) degraders of STAT3, SD-36 and SD-2301. STAT3 degraders effectively degraded STAT3 in dendritic cells and reprogrammed the dendritic cell-transcriptional network towards immunogenicity. Furthermore, STAT3 degrader monotherapy was efficacious in treatment of advanced tumours and ICB-resistant tumours without toxicity in mice. Thus, the crosstalk between STAT3 and STAT5 transcriptional pathways determines the dendritic cell phenotype in the tumour microenvironment and STAT3 degraders hold promise for cancer immunotherapy.

HDAC6 inhibition by ITF3756 modulates PD-L1 expression and monocyte phenotype: insights for a promising immune checkpoint blockade co-treatment therapy

Introduction

Tumor immunotherapy has revolutionized cancer treatment, particularly through the use of immune checkpoint inhibitors targeting the PD-L1/PD-1 axis. While PD-L1 expression on tumor cells is an established predictive biomarker for therapeutic response, emerging evidence highlights the importance of PD-L1 expression on myeloid cells, both in the periphery and within the tumor microenvironment (TME). This study explores the immunomodulatory effects of the selective HDAC6 inhibitor ITF3756 on monocytes and dendritic cells (DCs).

Methods

Monocytes were stimulated with the pro-inflammatory cytokine TNF-α and treated with ITF3756. PD-L1 and CD40 expression levels were assessed by flow cytometry. Transcriptomic and proteomic analyses were performed to characterize changes in gene and protein expression profiles. T cell proliferation was evaluated in co-culture assays. Additionally, the impact of ITF3756 was assessed in an in vivo murine model of colon cancer.

Results

ITF3756 effectively downregulated PD-L1 expression in TNF-α-activated monocytes and enhanced their costimulatory capacity by increasing CD40 expression. Transcriptomic and proteomic analyses revealed that ITF3756 counteracted TNF-α pathway activation and downregulated multiple inhibitory immune checkpoint molecules, promoting a less immunosuppressive phenotype. In co-culture assays, ITF3756-treated monocytes and DCs significantly enhanced T cell proliferation. In vivo, ITF3756 treatment led to reduced tumor growth in a colon cancer model.

Discussion

These findings demonstrate that selective HDAC6 inhibition by ITF3756 modulates myeloid cell functionality by diminishing inhibitory signals and promoting T cell activation. Thus, ITF3756 represents a promising immunomodulatory agent that could enhance the efficacy of immune checkpoint blockade in cancer immunotherapy.

Combination of immune checkpoint inhibitors and anthracyclines as a potential first-line regimen for dedifferentiated liposarcoma: systematic review and meta-analysis

INTRODUCTION

Dedifferentiated liposarcoma (DDLPS) is a rare and aggressive subtype of soft tissue sarcoma, characterized by limited treatment options and poor prognosis. Despite surgical resection being the only potentially curative treatment for localized DDLPS, the recurrence rate remains high, and systemic chemotherapy, typically anthracycline-based, shows limited efficacy in advanced stages. While immune checkpoint inhibitors (ICIs) have shown promise in various sarcoma subtypes, including DDLPS, their role as a first-line treatment remains unclear.

METHODS

We conducted a systematic meta-analysis to evaluate the efficacy of ICIs in treating patients with DDLPS. A total of 25 studies encompassing 245 patients were included. Data on overall response rate (ORR), progression-free survival, and grade III-V treatment-related adverse events were analyzed. We assessed treatment efficacy based on the line of therapy and treatment regimens, including ICI monotherapy, dual ICI therapy, and ICI combinations with other modalities.

RESULTS

The pooled ORR for all ICI-based treatments was 7%. First-line ICI therapy yielded a significantly higher ORR of 22%, compared to 4% in later-line treatment. The combination of ICI with anthracyclines demonstrated the highest ORR of 52%. In contrast, ICI regimens combined with trabectedin or other agents showed limited efficacy. Sensitivity analysis confirmed the stability of results, and publication bias was not detected.

CONCLUSION

This meta-analysis supports the potential role of ICIs, particularly in combination with anthracyclines, as a first-line therapeutic strategy for DDLPS. These results provide a foundation for future prospective studies aimed at optimizing immunotherapy approaches for this rare and challenging malignancy.

Spatially segregated APOE+ macrophages restrict immunotherapy efficacy in clear cell renal cell carcinoma

Background: Immunotherapy has revolutionized cancer treatment and holds great potential for them, including metastatic clear cell renal cell carcinoma (ccRCC). However, immune resistance remains a major obstacle, limiting its efficacy and durability. Understanding the mechanisms of immune tolerance in the tumor microenvironment (TME) is pivotal for overcoming these challenges and enhancing therapeutic outcomes. Methods: Over 2000 samples, including a real-world cohort of 230 advanced ccRCC patients treated with immune checkpoint blockade (ICB) were analyzed. Single-cell RNA sequencing data from 13 tumor regions were categorized into ICB-exposed, ICB-resistant, and ICB-responsive groups. Multiple robust algorithms and multiplex immunofluorescence were used to explore TME composition and macrophage heterogeneity. Spatial communication dynamics were further investigated. In vitro experiments were performed to evaluate the impact of SPP1 on 786-O and 769-P cells. Co-culture experiments with THP-1-derived macrophages, followed by Western blot, flow cytometry, and functional assays, were performed to investigate SPP1-mediated macrophage polarization and its impact on tumor progression. Results: The results revealed an elevated presence of Apolipoprotein E (APOE)+ macrophages in ICB-resistant ccRCC. Notably, higher APOE+ macrophage proportion indicated shorter prognosis and worse response to ICB (P < 0.001). Elevated expression of CCAAT Enhancer Binding Protein Delta (CEBPD) was markedly linked to several immunosuppressive pathways, hindering T cell recruitment, promoting exhaustion, ultimately diminishing poorer prognosis and worse ICB efficacy. Meanwhile, upregulated Secreted Phosphoprotein 1 (SPP1) significantly enhances the proliferation, clonal formation, and migration of ccRCC cells. Tumor-derived SPP1. Additionally, SPP1 signaling from malignant cells appeared to recruit APOE+ macrophages to tumor margins, and promotes macrophage polarization into APOE+ M2-like macrophages. In the vicinity of the tumor, these APOE+ macrophages shape immunosuppressive TME by releasing abundant TGF-β signals, limiting anti-tumor effector T cells activity in ICB-resistant tumors, and contributing to tumor progression. Conclusion: This study reveals the critical role of APOE+ macrophages in promoting immune suppression and resistance to ICB therapy in ccRCC. By promoting T cell exhaustion and immunosuppressive signaling, particularly via localized TGF-β, these spatially segregated macrophages undermine treatment efficacy. Targeting APOE+ macrophages, especially in conjunction with ICB, presents a promising strategy to overcome immune resistance and enhance outcomes for ccRCC patients.

Targeting tumor-intrinsic S100 calcium-binding protein A1 augments antitumor immunity and potentiates immunotherapy efficacy

Immune checkpoint blockade (ICB) has revolutionized cancer treatment, but the therapeutic response is highly heterogeneous, which highlights the necessity for developing predictive biomarkers and overcoming ICB resistance. Cancer cell-intrinsic features, especially those that can be dynamically monitored via liquid biopsy, represent a broader scope for biomarker development. In addition, a potential mode of ICB resistance is tumor-intrinsic mechanisms leading to an immunosuppressive tumor microenvironment (TME). However, the underlying interactive network remains elusive, and the generalizable biomarkers and targeting strategies are still lacking. Here, we uncovered the potential of plasma S100 calcium-binding protein A1 (S100A1) for determining ICB efficacy via liquid biopsy of patients with lung cancer. Multiomics and functional studies have suggested that tumor-intrinsic S100A1 expression correlated with an immunologically "cold" TME and resistance to ICB in multiple syngeneic murine tumors and tissue samples from patients with lung cancer. Mechanistic investigations demonstrated that interfering with the tumor-intrinsic S100A1/ubiquitin-specific protease 7/p65/granulocyte-macrophage colony-stimulating factor (GM-CSF) modulatory axis could potentiate an inflamed TME by promoting M1-like macrophage polarization and T cell function. GM-CSF priming was sufficient to enhance the ICB response in tumors with high S100A1 expression in preclinical models. These findings define S100A1 as a potential blood-based biomarker and a novel synergistic target for cancer immunotherapy.

New insights on anti-tumor immunity of CD8+ T cells: cancer stem cells, tumor immune microenvironment and immunotherapy

Recent breakthroughs in tumor immunotherapy have confirmed the capacity of the immune system to fight several cancers. The effective means of treating cancer involves accelerating the death of tumor cells and improving patient immunity. Dynamic changes in the tumor immune microenvironment alter the actual effects of anti-tumor drug production and may trigger favorable or unfavorable immune responses by modulating tumor-infiltrating lymphocytes. Notably, CD8+ T cells are one of the primary tumor-infiltrating immune cells that provide anti-tumor response. Tumor cells and tumor stem cells will resist or evade destruction through various mechanisms as CD8+ T cells exert their anti-tumor function. This paper reviews the research on the regulation of tumor development and prognosis by cancer stem cells that directly or indirectly alter the role of tumor-infiltrating CD8+ T cells. We also discuss related immunotherapy strategies.

The UBA1-STUB1 Axis Mediates Cancer Immune Escape and Resistance to Checkpoint Blockade

SIGNIFICANCE

Our study reveals UBA1 as a predictive biomarker for clinical outcomes in ICB cohorts, mediating cancer immune evasion and ICB resistance. We further highlight JAK1 stabilization as a key mechanism of UBA1 inhibition and nominate the UBA1-STUB1 axis as an immuno-oncology therapeutic target to improve the efficacy of ICB.

An OMV-Based Nanovaccine as Antigen Presentation Signal Enhancer for Cancer Immunotherapy

Antigen-presenting cells (APCs) process tumor vaccines and present tumor antigens as the first signals to T cells to activate anti-tumor immunity, which process requires the assistance of co-stimulatory second signals on APCs. The immune checkpoint programmed death ligand 1 (PD-L1) not only mediates the immune escape of tumor cells but also acts as a co-inhibitory second signal on APCs. The serious dysfunction of second signals due to the high expression of PD-L1 on APCs in the tumor body results in the inefficiency of tumor vaccines. To overcome this challenge, a previously established Plug-and-Display tumor vaccine platform based on bacterial outer membrane vesicles (OMVs) is developed into an "Antigen Presentation Signal Enhancer" (APSE) by surface-modifying PD-L1 antibodies (αPD-L1). While delivering tumor antigens, APSE can activate the expression of co-stimulatory second signals in APCs due to the high immunogenicity of OMVs. More importantly, the surface-modified αPD-L1 binds to the co-inhibitory signals PD-L1, potentially restoring CD80 function and ensuring efficient co-stimulatory second signals and activation of anti-tumor immunity. The results reveal the importance of PD-L1 blockage in the initiation process of anti-tumor immunity, and the second signal modulation capability of APSE can expand the application potential of cancer vaccines to less immunogenic malignancies.

The Role of Chronic Inflammation in Pediatric Cancer

Inflammation plays a crucial role in wound healing and the host immune response following pathogenic invasion. However, unresolved chronic inflammation can result in tissue fibrosis and genetic alterations that contribute to the pathogenesis of human diseases such as cancer. Recent scientific advancements exploring the underlying mechanisms of malignant cellular transformations and cancer progression have exposed significant disparities between pediatric and adult-onset cancers. For instance, pediatric cancers tend to have lower mutational burdens and arise in actively developing tissues, where cell-cycle dysregulation leads to gene, chromosomal, and fusion gene development not seen in adult-onset counterparts. As such, scientific findings in adult cancers cannot be directly applied to pediatric cancers, where unique mutations and inherent etiologies remain poorly understood. Here, we review the role of chronic inflammation in processes of genetic and chromosomal instability, the tumor microenvironment, and immune response that result in pediatric tumorigenesis transformation and explore current and developing therapeutic interventions to maintain and/or restore inflammatory homeostasis.

Tumor-treating fields in cancer therapy: advances of cellular and molecular mechanisms

Tumor-Treating Fields (TTFields) use intermediate-frequency and low-intensity electric fields to inhibit tumor cells. However, their mechanisms are still not well understood. This article reviews their key antitumor mechanisms at the cellular and molecular levels, including inhibition of proliferation, induction of death, disturbance of migration, and activation of the immune system. The multifaceted biological effects in combination with other cancer treatments are also summarized. The deep insight into their mechanism will help develop more potential antitumor treatments.

LKB1 dictates sensitivity to immunotherapy through Skp2-mediated ubiquitination of PD-L1 protein in non-small cell lung cancer

BACKGROUND

Loss-of-function mutations of liver kinase B (LKB1, also termed as STK11 (serine/threonine kinase 11)) are frequently detected in patients with non-small cell lung cancer (NSCLC). The LKB1 mutant NSCLC was refractory to almost all the antitumor treatments, including programmed cell death protein 1 (PD-1)/programmed death-ligand 1 (PD-L1) blockade therapy. Unfortunately, mechanisms underlying resistance to immunotherapy are not fully understood. In this study, we deciphered how LKB1 regulated sensitivity to anti-PD-1/PD-L1 immunotherapy.

METHODS

We investigated the mutational landscape of LKB1 mutant NSCLC in next generation sequencing (NGS) data sets. Expression of LKB1, PD-L1 and S-phase kinase-associated protein 2 (Skp2) in NSCLC samples were assessed by immunohistochemistry (IHC). The tumor microenvironment (TME) profiling of LKB1 wild type (WT) and mutant NSCLC was performed using fluorescent multiplex IHC. Mass spectrometry and enrichment analysis were used to identify LKB1 interacting proteins. Mechanistic pathways were explored by immunoblotting, ubiquitination assay, cycloheximide chase assay and immunoprecipitation assay.

RESULTS

By using NGS data sets and histological approaches, we demonstrated that LKB1 status was positively associated with PD-L1 protein expression and conferred a T cell-enriched "hot" TME in NSCLC. Patients with good responses to anti-PD-1/PD-L1 immunotherapy possessed a high level of LKB1 and PD-L1. Skp2 emerged as the molecular hub connecting LKB1 and PD-L1, by which Skp2 catalyzed K63-linked polyubiquitination on K136 and K280 residues to stabilize PD-L1 protein. Inhibition of Skp2 expression by short hairpin RNA or its E3 ligase activity by compound #25 abrogated intact expression of PD-L1 in vitro and generated a T cell-excluded "cold" TME in vivo. Thus, the LKB1-Skp2-PD-L1 regulatory loop was crucial for retaining PD-L1 protein expression and manipulation of this pathway would be a feasible approach for TME remodeling.

CONCLUSION

LKB1 and Skp2 are required for intact PD-L1 protein expression and TME remodeling in NSCLC. Inhibition of Skp2 resulted in a conversion from "hot" TME to "cold" TME and abrogated therapeutic outcomes of immunotherapy. Screening LKB1 and Skp2 status would be helpful to select recipients who may benefit from anti-PD-1/PD-L1 immunotherapy.

Tumor-Infiltrating Immune Cells and HLA Expression as Potential Biomarkers Predicting Response to PD-1 Inhibitor Therapy in Stage IV Melanoma Patients

PD-1 inhibitors are known to be effective in melanoma; however, a considerable proportion of patients fail to respond to therapy, necessitating the identification of predictive markers. We examined the predictive value of tumor cell HLA class I and II expression and immune cell infiltration in melanoma patients treated with PD-1 inhibitors. Pretreatment surgical samples from 40 stage IV melanoma patients were studied immunohistochemically for melanoma cell expression of HLA class I molecules (using four antibody clones with different specificities), HLA-II, and immune cell infiltration (using a panel of 10 markers). Among the responders, the ratio of patients showing melanoma cell HLA-II expression was higher compared to non-responders (p = 0.0158), and similar results were obtained in the case of two anti-HLA-I antibodies. A combined score of HLA-I/II expression also predicted treatment response (p = 0.0019). Intratumoral infiltration was stronger in the responders for most immune cell types. Progression-free survival showed an association with HLA-II expression, the combined HLA score, and the density of immune cells expressing CD134 and PD-1, while overall survival was significantly associated only with HLA class II expression. Our findings corroborate previous results indicating the importance of immune cell infiltration and tumor cell HLA-II expression in the efficacy of PD-1 inhibitor treatment in a "real world" patient cohort and suggest the potential predictive role of HLA class I expression.

Metabolism and macrophages in the tumor microenvironment

Tumor-associated macrophages (TAMs) constitute the primary subset of immune cells within the tumor microenvironment (TME). Exhibiting both phenotypic and functional heterogeneity, TAMs play distinct roles in tumor initiation, progression, and responses to therapy in patients with cancer. In response to various immune and metabolic cues within the TME, TAMs dynamically alter their metabolic profiles to adapt. Changes in glucose, amino acid, and lipid metabolism in TAMs, as well as their interaction with oncometabolites, not only sustain their energy demands but also influence their impact on tumor immune responses. Understanding the molecular mechanisms underlying the metabolic reprogramming of TAMs and their orchestration of metabolic processes can offer insights for the development of novel cancer immunotherapies targeting TAMs. Here, we discuss how metabolism reprograms macrophages in the TME and review clinical trials aiming to normalize metabolic alterations in TAMs and alleviate TAM-mediated immune suppression and protumor activity.

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.

Multi-platform biomarkers of response to an immune checkpoint inhibitor in the neoadjuvant I-SPY 2 trial for early-stage breast cancer

Only a subset of patients with breast cancer responds to immune checkpoint blockade (ICB). To better understand the underlying mechanisms, we analyze pretreatment biopsies from patients in the I-SPY 2 trial who receive neoadjuvant ICB using multiple platforms to profile the tumor microenvironment. A variety of immune cell populations and markers of immune/cytokine signaling associate with pathologic complete response (pCR). Interestingly, these differ by breast cancer receptor subtype. Measures of the spatial distributions of immune cells within the tumor microenvironment, in particular colocalization or close spatial proximity of PD-1+ T cells with PD-L1+ cells (immune and tumor cells), are significantly associated with response in the overall cohort as well as the in the triple negative (TN) and HR+HER2- subtypes. Our findings indicate that biomarkers associated with immune cell signaling, immune cell densities, and spatial metrics are predictive of neoadjuvant ICB efficacy in breast cancer.

Genetic absence of PD-L1 does not restore CD8+ T cell function during respiratory virus infection and delays virus clearance

A key mediator of T cell impairment during respiratory virus infection is the inhibitory receptor PD-1. PD-1 is induced on T cells following antigen exposure, whereas proinflammatory cytokines upregulate the ligands PD-L1 and PD-L2. Respiratory virus infection leads to upregulation of PD-L1 on airway epithelial cells, dendritic cells, and alveolar macrophages. However, the role of PD-L1 on different cell types in acute respiratory virus infections is not known. We sought to determine the role of PD-L1 on different cell types in CD8+ T cell impairment. We found that PD-L1-/- mice challenged with human metapneumovirus or influenza showed a similar level of CD8+ T cell impairment compared to wild-type (WT) mice. Moreover, virus clearance was delayed in PD-L1-/- mice compared to WT. CD8+ T cells from PD-L1-deficient mice expressed higher levels of inhibitory receptors both at baseline and after respiratory virus infection. The antibody blockade of PD-L2 failed to restore function to the impaired cells. While reciprocal bone marrow chimeras between WT and PD-L1-/- mice did not restore CD8+ T cell function after the respiratory virus challenge, mice that received the PD-L1-/- bone marrow had higher inhibitory receptor expression on CD8+ cells. This discrepancy in the inhibitory receptor expression suggests that cells of the hematopoietic compartment contribute to T cell impairment on CD8+ T cells.IMPORTANCEThe phenomenon of pulmonary CD8+ T cell impairment with diminished antiviral function occurs during acute respiratory virus infection mediated by Programmed Cell Death-1 (PD-1) signaling. Moreover, PD-1 blockade enhances T cell function to hasten viral clearance. The ligand PD-L1 is expressed in many cell types, but which cells drive lung T cell impairment is not known. We used genetic approaches to determine the contribution of PD-L1 on lung T cell impairment. We found that PD-L2 cannot compensate for the loss of PD-L1, and PD-L1-deficient mice exhibit increased expression of other inhibitory receptors. Bone marrow chimeras between PD-L1-deficient and wild-type mice indicated that hematopoietic PD-L1 expression is associated with inhibitory receptor upregulation and impairment.

PD-L1 restrains PD-1+Nrp1lo Treg cells to suppress inflammation-driven colorectal tumorigenesis

T cells function not only as an essential component of host cancer immunosurveillance but also as a regulator of colonic inflammation, a process that promotes colorectal cancer. Programmed death-ligand 1 (PD-L1) is a T cell-negative regulator, but its role in regulation of T cell functions in the context of colorectal cancer is unknown. We report that global deletion of Cd274 results in increased colonic inflammation, PD-1+ T cells, and inflammation-driven colorectal tumorigenesis in mice. Single-cell RNA sequencing (scRNA-seq) analysis revealed that PD-L1 suppresses subpopulations of programmed cell death protein 1 (PD-1)+Nrp1lo regulatory T (Treg) cells and interleukin (IL) 6+ neutrophils in colorectal tumor. Treg cells produce transforming growth factor (TGF) β to recruit IL6+ neutrophils. Neutrophils produce IL6 to inhibit activation of tumor-specific cytotoxic T lymphocytes (CTLs) and primary CTLs. Accordingly, IL6 blockade immunotherapy increases CTL activation and suppresses colon tumor growth in vivo. Our findings determine that PD-L1 restrains PD-1+Nrp1loTGFβ+ Treg cells to suppress IL6+ neutrophil tumor recruitment to sustain CTL activation to control inflammation-driven colorectal tumorigenesis.

Inhibition of the Rho/MRTF pathway improves the response of BRAF-resistant melanoma to PD1/PDL1 blockade

Metastatic cutaneous melanoma is a fatal skin cancer. Resistance to targeted and immune therapies limits the benefits of current treatments. Identifying and adding anti-resistance agents to current treatment protocols can potentially improve clinical responses. Myocardin-related transcription factor (MRTF) is a transcriptional coactivator whose activity is indirectly regulated by actin and the Rho family of GTPases. We previously demonstrated that development of BRAF inhibitor (BRAFi) resistance frequently activates the Rho/MRTF pathway in human and mouse BRAFV600E melanomas. In clinical trials, pretreatment with BRAFi reduces the benefit of immune therapies. We aimed to test the efficacy of concurrent treatment with our MRTF pathway inhibitor CCG-257081 and anti-PD1 in vivo and to examine its effects on the melanoma immune microenvironment. Because MRTF pathway activation upregulates the expression of immune checkpoint inhibitor genes/proteins, we asked whether CCG-257081 can improve the response to immune checkpoint blockade. CCG-257081 reduced the expression of PDL1 in BRAFi-resistant melanoma cells and decreased surface PDL1 levels on both BRAFi-sensitive and -resistant melanoma cells. Using our recently described murine vemurafenib-resistant melanoma model, we found that CCG-257081, in combination with anti-PD1 immune therapy, reduced tumor growth and increased survival. Moreover, anti-PD1/CCG-257081 co-treatment increased infiltration of CD8+ T cells and B cells into the tumor microenvironment and reduced tumor-associated macrophages. Here, we propose CCG-257081 as an anti-resistance and immune therapy-enhancing anti-melanoma agent.

Targeted protein degradation combined with PET imaging reveals the role of host PD-L1 in determining anti-PD-1 therapy efficacy

PURPOSE

Immunohistochemical staining of programmed death-ligand 1 (PD-L1) in tumor biopsies acquired through invasive procedures is routinely employed in clinical practice to identify patients who are most likely to benefit from anti-programmed cell death protein 1 (PD-1) therapy. Nevertheless, PD-L1 expression is observed in various cellular subsets within tumors and their microenvironments, including tumor cells, dendritic cells, and macrophages. The impact of PD-L1 expression across these different cell types on the responsiveness to anti-PD-1 treatment is yet to be fully understood.

METHODS

We synthesized polymer-based lysosome-targeting chimeras (LYTACs) that incorporate both PD-L1-targeting motifs and liver cell-specific asialoglycoprotein receptor (ASGPR) recognition elements. Small-animal positron emission tomography (PET) imaging of PD-L1 expression was also conducted using a PD-L1-specific radiotracer 89Zr-αPD-L1/Fab.

RESULTS

The PD-L1 LYTAC platform was capable of specifically degrading PD-L1 expressed on liver cancer cells through the lysosomal degradation pathway via ASGPR without impacting the PD-L1 expression on host cells. When coupled with whole-body PD-L1 PET imaging, our studies revealed that host cell PD-L1, rather than tumor cell PD-L1, is pivotal in the antitumor response to anti-PD-1 therapy in a mouse model of liver cancer.

CONCLUSION

The LYTAC strategy, enhanced by PET imaging, has the potential to surmount the limitations of knockout mouse models and to provide a versatile approach for the selective degradation of target proteins in vivo. This could significantly aid in the investigation of the roles and mechanisms of protein functions associated with specific cell subsets in living subjects.

MHC-I and PD-L1 Expression is Associated with Decreased Tumor Outgrowth and is Radiotherapy-inducible in the Murine Head and Neck Squamous Cell Carcinoma Model MOC1

INTRODUCTION

Combined radiotherapy and immune checkpoint inhibition is a potential treatment option for head and neck squamous cell carcinoma (HNSCC). Immunocompetent mouse models can help to successfully develop radio- immunotherapy combinations and to increase our understanding of the effects of radiotherapy on the tumor microenvironment for future clinical translation. Therefore, the aim of this study was to develop a homogeneous, reproducible HNSCC model originating from the Mouse Oral Cancer 1 (MOC1) HNSCC cell line, and to explore the radiotherapy-induced changes in its tumor microenvironment, using flow cytometry and PD-L1 microSPECT/CT imaging.

MATERIALS AND METHODS

In vivo growing tumors originating from the parental MOC1 line were used to generate single cell derived clones. These clones were screened in vitro for their ability to induce programmed cell death ligand 1 (PD-L1) and major histocompatibility complex class I (MHC-I) following IFNγ exposure. Clones with different IFNγ sensitivity were inoculated in C57BL/6 mice and assessed for tumor outgrowth. The composition of the tumor microenvironment of a stably growing (non)irradiated MOC1-derived clone was assessed by immunohistochemistry, flow cytometry and PD-L1 microSPECT/CT.

RESULTS

Low in vitro inducibility of MHC-I and PD-L1 by IFNγ was associated with increased tumor outgrowth of MOC1 clones in vivo. Flow cytometry analysis of cells derived from a stable in vivo growing MOC1 clone MOC1.3D5low showed expression of MHC-I and PD-L1 on several cell populations within the tumor. Upon irradiation, MHC-I and PD-L1 increased on leukocytes (CD45.2+) and cancer associated fibroblasts (CD45.2-/EpCAM-/CD90.1+). Furthermore, PD-L1 microSPECT/CT showed increased tumor uptake of radiolabeled PD-L1 antibodies with a heterogeneous spatial distribution of the radio signal, which co-localized with PD-L1+ and CD45.2+ areas.

DISCUSSION

PD-L1 and MHC-I inducibility by IFNγ in vitro is associated with tumor outgrowth of MOC1 clones in vivo. In tumors originating from a stably growing MOC1-derived clone, expression of these immune-related markers was induced by irradiation shown by flow cytometry on several cell populations within the tumor microenvironment such as immune cells and cancer associated fibroblasts. PD-L1 microSPECT/CT showed increased tumor uptake following radiotherapy, and autoradiography showed correlation of uptake with areas that are heavily infiltrated by immune cells. Knowledge of radiotherapy-induced effects on the tumor microenvironment in this model can help optimize timing and dosage for radio- immunotherapy combination strategies in future research.

ITGB4 Serves as an Identification and Prognosis Marker Associated with Immune Infiltration in Small Cell Lung Carcinoma

Integrin beta 4 (ITGB4) is a vital factor for numerous cancers. However, no reports regarding ITGB4 in small cell lung carcinoma (SCLC) have been found in the existing literature. This study systematically investigated the expression and clinical value of ITGB4 in SCLC using multi-center and large-sample (n = 963) data. The ITGB4 expression levels between SCLC and control tissues were compared using standardized mean difference and Wilcoxon rank-sum test. The clinical significance of the gene in SCLC was observed using Cox regression and Kaplan-Meier curves. ITGB4 is overexpressed in multiple cancers and represents significant value in distinguishing among cancer samples (AUC = 0.91) and predicting the prognoses (p < 0.05) of patients with different cancers. In contrast, decreased ITGB4 mRNA expression was determined in SCLC (SMD < 0), and this finding was further confirmed at protein levels using in-house specimens (p < 0.05). This decrease in expression may be attributed to the regulatory role of estrogen receptor 1. ITGB4 may participate in the progression of SCLC by affecting several signaling pathways (e.g., tumor necrosis factor signaling pathway) and a series of immune cells (e.g., dendritic cells) (p < 0.05). The gene may serve as a potential marker for predicting the disease status (AUC = 0.97) and prognoses (p < 0.05) of patients with SCLC. Collectively, ITGB4 was identified as an identification and prognosis marker associated with immune infiltration in SCLC.

A novel vesicular stomatitis virus armed with IL-2 mimic for oncolytic therapy

Oncolytic virus (OV) is increasingly being recognized as a novel vector in cancer immunotherapy. Increasing evidence suggests that OV has the ability to change the immune status of tumor microenvironment, so called transformation of 'cold' tumors into 'hot' tumors. The improved anti-tumor immunity can be induced by OV and further enhanced through the combination of various immunomodulators. The Neo-2/15 is a newly de novo synthesized cytokine that functions as both IL-2 and IL-15. However, it specifically lacks the binding site of IL-2 receptor α subunit (CD25), therefore unable to induce the Treg proliferation. In present study, a recombinant vesicular stomatitis virus expressing the Neo-2/15 (VSVM51R-Neo-2/15) was generated. Intratumoral delivery of VSVM51R-Neo-2/15 efficiently inhibited tumor growth in mice without causing the IL-2-related toxicity previously observed in clinic. Moreover, treatment with VSVM51R-Neo-2/15 increased the number of activated CD8+ T cells but not Treg cells in tumors. More tumor-bearing mice were survival with VSVM51R-Neo-2/15 treatment, and the surviving mice displayed enhanced protection against tumor cell rechallenge due to the induced anti-tumor immunity. In addition, combination therapy of OV and anti-PD-L1 immune checkpoint inhibitors further enhanced the anti-tumor immune response. These findings suggest that our novel VSVM51R-Neo-2/15 can effectively inhibit the tumor growth and enhance the sensitivity to immune checkpoint inhibitors, providing promising attempts for further clinical trials.

Centipeda minima and 6-O-angeloylplenolin enhance the efficacy of immune checkpoint inhibitors in non-small cell lung cancer

BACKGROUND

Chemotherapeutic agents including cisplatin, gemcitabine, and pemetrexed, significantly enhance the efficacy of immune checkpoint inhibitors (ICIs) in non-small cell lung cancer (NSCLC) by increasing PD-L1 expression and potentiating T cell cytotoxicity. However, the low response rate and adverse effects limit the application of chemotherapy/ICI combinations in patients.

METHODS

We screened for medicinal herbs that could perturb PD-L1 expression and enhance T cell cytotoxicity in the presence of anti-PD-L1 antibody, and investigated the underlying mechanisms.

RESULTS

We found that the aqueous extracts of Centipeda minima (CM) significantly enhanced the cancer cell-killing activity and granzyme B expression level of CD8+ T cells, in the presence of anti-PD-L1 antibody. Both CM and its active component 6-O-angeloylplenolin (6-OAP) upregulated PD-L1 expression by suppressing GSK-3β-β-TRCP-mediated ubiquitination and degradation. CM and 6-OAP significantly enhanced ICI-induced reduction of tumor burden and prolongation of overall survival of mice bearing NSCLC cells, accompanied by upregulation of PD-L1 and increase of CD8+ T cell infiltration. CM also exhibited anti-NSCLC activity in cells and in a patient-derived xenograft mouse model.

CONCLUSIONS

These data demonstrated that the induced expression of PD-L1 and enhancement of CD8+ T cell cytotoxicity underlay the beneficial effects of 6-OAP-rich CM in NSCLCs, providing a clinically available and safe medicinal herb for combined use with ICIs to treat this deadly disease.

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.

Pulsed Photothermal Therapy of Solid Tumors as a Precondition for Immunotherapy

Photothermal therapy (PTT) refers to the use of plasmonic nanoparticles to convert electromagnetic radiation in the near infrared region to heat and kill tumor cells. Continuous wave lasers have been used clinically to induce PTT, but the treatment is associated with heat-induced tissue damage that limits usability. Here, the engineering and validation of a novel long-pulsed laser device able to induce selective and localized mild hyperthermia in tumors while reducing the heat affected zone and unwanted damage to surrounding tissue are reported. Long-pulsed PTT induces acute necrotic cell death in heat affected areas and the release of tumor associated antigens. This antigen release triggers maturation and stimulation of CD80/CD86 in dendritic cells in vivo that primes a cytotoxic T cell response. Accordingly, long-pulsed PTT enhances the therapeutic effects of immune checkpoint inhibition and increases survival of mice with bladder cancer. Combined, the data promote long-pulsed PTT as a safe and effective strategy for enhancing therapeutic responses to immune checkpoint inhibitors while minimizing unwanted tissue damage.

Understanding tissue-resident macrophages unlocks the potential for novel combinatorial strategies in breast cancer

Tissue-resident macrophages (TRMs) are an integral part of the innate immune system, but their biology is not well understood in the context of cancer. Distinctive resident macrophage populations are identified in different organs in mice using fate mapping studies. They develop from the yolk sac and self-maintain themselves lifelong in specific tissular niches. Similarly, breast-resident macrophages are part of the mammary gland microenvironment. They reside in the breast adipose tissue stroma and close to the ductal epithelium and help in morphogenesis. In breast cancer, TRMs may promote disease progression and metastasis; however, precise mechanisms have not been elucidated. TRMs interact intimately with recruited macrophages, cytotoxic T cells, and other immune cells along with cancer cells, deciding further immunosuppressive or cytotoxic pathways. Moreover, triple-negative breast cancer (TNBC), which is generally associated with poor outcomes, can harbor specific TRM phenotypes. The influence of TRMs on adipose tissue stroma of the mammary gland also contributes to tumor progression. The complex crosstalk between TRMs with T cells, stroma, and breast cancer cells can establish a cascade of downstream events, understanding which can offer new insight for drug discovery and upcoming treatment choices. This review aims to acknowledge the previous research done in this regard while exploring existing research gaps and the future therapeutic potential of TRMs as a combination or single agent in breast cancer.

IL-4/IL-4R axis signaling drives resistance to immunotherapy by inducing the upregulation of Fcγ receptor IIB in M2 macrophages

In recent years, immunotherapy, particularly PD-1 antibodies, have significantly enhanced the outcome of gastric cancer patients. Despite these advances, some patients do not respond well to treatment, highlighting the need to understand resistance mechanisms and develop predictive markers of treatment effectiveness. This study retrospectively analyzed data from 106 patients with stage IV gastric cancer who were treated with first-line immunotherapy in combination with chemotherapy. By comparing plasma cytokine levels between patients resistant and sensitive to PD-1 antibody therapy, the researchers identified elevated IL-4 expression in the resistant patients. Mechanical investigations revealed that IL-4 induces metabolic changes in macrophages that activate the PI3K/AKT/mTOR pathway. This alteration promotes ATP production, enhances glycolysis, increases lactic acid production, and upregulates FcγRIIB expression in macrophages. Ultimately, these changes lead to CD8+ T cell dysfunction and resistance to PD-1 antibody therapy in gastric cancer. These findings highlight the role of IL-4-induced macrophage polarization and metabolic reprogramming in immune resistance and verify IL-4 as potential targets for improving treatment outcomes in gastric cancer patients.

Radiotherapy and immunology

The majority of cancer patients receive radiotherapy during the course of treatment, delivered with curative intent for local tumor control or as part of a multimodality regimen aimed at eliminating distant metastasis. A major focus of research has been DNA damage; however, in the past two decades, emphasis has shifted to the important role the immune system plays in radiotherapy-induced anti-tumor effects. Radiotherapy reprograms the tumor microenvironment, triggering DNA and RNA sensing cascades that activate innate immunity and ultimately enhance adaptive immunity. In opposition, radiotherapy also induces suppression of anti-tumor immunity, including recruitment of regulatory T cells, myeloid-derived suppressor cells, and suppressive macrophages. The balance of pro- and anti-tumor immunity is regulated in part by radiotherapy-induced chemokines and cytokines. Microbiota can also influence radiotherapy outcomes and is under clinical investigation. Blockade of the PD-1/PD-L1 axis and CTLA-4 has been extensively investigated in combination with radiotherapy; we include a review of clinical trials involving inhibition of these immune checkpoints and radiotherapy.

PIKfyve controls dendritic cell function and tumor immunity

The modern armamentarium for cancer treatment includes immunotherapy and targeted therapy, such as protein kinase inhibitors. However, the mechanisms that allow cancer-targeting drugs to effectively mobilize dendritic cells (DCs) and affect immunotherapy are poorly understood. Here, we report that among shared gene targets of clinically relevant protein kinase inhibitors, high PIKFYVE expression was least predictive of complete response in patients who received immune checkpoint blockade (ICB). In immune cells, high PIKFYVE expression in DCs was associated with worse response to ICB. Genetic and pharmacological studies demonstrated that PIKfyve ablation enhanced DC function via selectively altering the alternate/non-canonical NF-κB pathway. Both loss of Pikfyve in DCs and treatment with apilimod, a potent and specific PIKfyve inhibitor, restrained tumor growth, enhanced DC-dependent T cell immunity, and potentiated ICB efficacy in tumor-bearing mouse models. Furthermore, the combination of a vaccine adjuvant and apilimod reduced tumor progression in vivo. Thus, PIKfyve negatively controls DCs, and PIKfyve inhibition has promise for cancer immunotherapy and vaccine treatment strategies.

PIKfyve, expressed by CD11c-positive cells, controls tumor immunity

Cancer treatment continues to shift from utilizing traditional therapies to targeted ones, such as protein kinase inhibitors and immunotherapy. Mobilizing dendritic cells (DC) and other myeloid cells with antigen presenting and cancer cell killing capacities is an attractive but not fully exploited approach. Here, we show that PIKFYVE is a shared gene target of clinically relevant protein kinase inhibitors and high expression of this gene in DCs is associated with poor patient response to immune checkpoint blockade (ICB) therapy. Genetic and pharmacological studies demonstrate that PIKfyve ablation enhances the function of CD11c+ cells (predominantly dendritic cells) via selectively altering the non-canonical NF-κB pathway. Both loss of Pikfyve in CD11c+ cells and treatment with apilimod, a potent and specific PIKfyve inhibitor, restrained tumor growth, enhanced DC-dependent T cell immunity, and potentiated ICB efficacy in tumor-bearing mouse models. Furthermore, the combination of a vaccine adjuvant and apilimod reduced tumor progression in vivo. Thus, PIKfyve negatively regulates the function of CD11c+ cells, and PIKfyve inhibition has promise for cancer immunotherapy and vaccine treatment strategies.

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.

The Immune Response of Cancer Cells in Breast and Gynecologic Neoplasms

Cancer diseases constitute a major health problem which leads to the death of millions of people annually. They are unique among other diseases because cancer cells can perfectly adapt to the environment that they create themselves. This environment is usually highly hostile and for normal cells it would be hugely difficult to survive, however neoplastic cells not only can survive but also manage to proliferate. One of the reasons is that they can alter immunological pathways which allow them to be flexible and change their phenotype to the one needed in specific conditions. The aim of this paper is to describe some of these immunological pathways that play significant roles in gynecologic neoplasms as well as review recent research in this field. It is of high importance to possess extensive knowledge about these processes, as greater understanding leads to creating more specialized therapies which may prove highly effective in the future.

DUX4 is a common driver of immune evasion and immunotherapy failure in metastatic cancers

Cancer immune evasion contributes to checkpoint immunotherapy failure in many patients with metastatic cancers. The embryonic transcription factor DUX4 was recently characterized as a suppressor of interferon-γ signaling and antigen presentation that is aberrantly expressed in a small subset of primary tumors. Here, we report that DUX4 expression is a common feature of metastatic tumors, with ~10-50% of advanced bladder, breast, kidney, prostate, and skin cancers expressing DUX4. DUX4 expression is significantly associated with immune cell exclusion and decreased objective response to PD-L1 blockade in a large cohort of urothelial carcinoma patients. DUX4 expression is a significant predictor of survival even after accounting for tumor mutational burden and other molecular and clinical features in this cohort, with DUX4 expression associated with a median reduction in survival of over 1 year. Our data motivate future attempts to develop DUX4 as a biomarker and therapeutic target for checkpoint immunotherapy resistance.

Metabolic adaptations determine whether natural killer cells fail or thrive within the tumor microenvironment

Natural Killer (NK) cells are a top contender in the development of adoptive cell therapies for cancer due to their diverse antitumor functions and ability to restrict their activation against nonmalignant cells. Despite their success in hematologic malignancies, NK cell-based therapies have been limited in the context of solid tumors. Tumor cells undergo various metabolic adaptations to sustain the immense energy demands that are needed to support their rapid and uncontrolled proliferation. As a result, the tumor microenvironment (TME) is depleted of nutrients needed to fuel immune cell activity and contains several immunosuppressive metabolites that hinder NK cell antitumor functions. Further, we now know that NK cell metabolic status is a main determining factor of their effector functions. Hence, the ability of NK cells to withstand and adapt to these metabolically hostile conditions is imperative for effective and sustained antitumor activity in the TME. With this in mind, we review the consequences of metabolic hostility in the TME on NK cell metabolism and function. We also discuss tumor-like metabolic programs in NK cell induced by STAT3-mediated expansion that adapt NK cells to thrive in the TME. Finally, we examine how other approaches can be applied to enhance NK cell metabolism in tumors.

Bifunctional molecular probe targeting tumor PD-L1 enhances anti-tumor efficacy by promoting ferroptosis in lung cancer mouse model

PURPOSE

Immune checkpoint inhibitors (ICIs) targeting tumor-specific PD-1/PD-L1 significantly improve the overall survival rate of patients with advanced cancer by reactivating the immune system to attack cancer cells. To explore their tumor killing effect, we used the radionuclide iodine-131 (131I) to label the anti-PD-L1 antibody Atezolizumab (131I-PD-L1 mAb).

METHOD

We prepared the radioimmunoassay molecular probe 131I-PD-L1 mAb by the chloramine-T method and evaluated its affinity using Lewis lung cancer (LLC) cells. The uptake of 131I-PD-L1 mAb by transplanted tumors was examined through SPECT and its in vivo distribution. We then compared the in vitro and in vivo anti-tumor efficacy of groups treated with control, PD-L1 mAb, 131I-PD-L1 mAb, and 131I-PD-L1 mAb + PD-L1 mAb combined treatment. We performed H&E staining to examine the changes in tumor, as well as the damage in major tissues and organs caused by potential side effects. The anti-tumor mechanism of 131I-PD-L1 mAb was analyzed by Western blot, RT-qPCR and immunohistochemistry (IHC).

RESULT

131I-PD-L1 mAb was highly stable and specific, and easily penetrated into tumor. 131I-PD-L1 mAb suppressed cancer cell proliferation in vitro, and inhibited tumor growth in vivo by inducing ferroptosis, thus prolonging the survival of experimental animals while demonstrating biological safety.

CONCLUSION

Therefore, our study suggested that 131I-PD-L1 mAb affected the expression of tumor-related factors through β-rays and thus promoted ferroptosis in tumor. Combined treatment showed better anti-tumor effect compared to single ICI treatment.

Role of Tumor-Associated Macrophages in Cervical Cancer: Integrating Classical Perspectives with Recent Technological Advances

Tumor-associated macrophages (TAMs) play a pivotal role in the tumor microenvironment, influencing cancer progression and contributing to poor prognosis. However, in cervical cancer (CC), their significance and involvement are relatively less studied than in other gynecological cancers such as ovarian and endometrial cancer. This review aims to provide an overview of TAMs, covering their origins and phenotypes and their impact on CC progression, along with major TAM-targeted therapeutic approaches. Furthermore, we advocate for the integration of cutting-edge research methodologies, such as single-cell RNA sequencing and spatial RNA sequencing, to enable in-depth and comprehensive investigations into TAMs in CC, which would be beneficial in leading to more personalized and effective immunotherapy strategies for patients with CC.

Harnessing innate immune pathways for therapeutic advancement in cancer

The innate immune pathway is receiving increasing attention in cancer therapy. This pathway is ubiquitous across various cell types, not only in innate immune cells but also in adaptive immune cells, tumor cells, and stromal cells. Agonists targeting the innate immune pathway have shown profound changes in the tumor microenvironment (TME) and improved tumor prognosis in preclinical studies. However, to date, the clinical success of drugs targeting the innate immune pathway remains limited. Interestingly, recent studies have shown that activation of the innate immune pathway can paradoxically promote tumor progression. The uncertainty surrounding the therapeutic effectiveness of targeted drugs for the innate immune pathway is a critical issue that needs immediate investigation. In this review, we observe that the role of the innate immune pathway demonstrates heterogeneity, linked to the tumor development stage, pathway status, and specific cell types. We propose that within the TME, the innate immune pathway exhibits multidimensional diversity. This diversity is fundamentally rooted in cellular heterogeneity and is manifested as a variety of signaling networks. The pro-tumor effect of innate immune pathway activation essentially reflects the suppression of classical pathways and the activation of potential pro-tumor alternative pathways. Refining our understanding of the tumor's innate immune pathway network and employing appropriate targeting strategies can enhance our ability to harness the anti-tumor potential of the innate immune pathway and ultimately bridge the gap from preclinical to clinical application.

TMEM160 promotes tumor immune evasion and radiotherapy resistance via PD-L1 binding in colorectal cancer

BACKGROUND

The effectiveness of anti-programmed cell death protein 1(PD-1)/programmed cell death 1 ligand 1(PD-L1) therapy in treating certain types of cancer is associated with the level of PD-L1. However, this relationship has not been observed in colorectal cancer (CRC), and the underlying regulatory mechanism of PD-L1 in CRC remains unclear.

METHODS

Binding of TMEM160 to PD-L1 was determined by co-immunoprecipitation (Co-IP) and GST pull-down assay.The ubiquitination levels of PD-L1 were verified using the ubiquitination assay. Phenotypic experiments were conducted to assess the role of TMEM160 in CRC cells. Animal models were employed to investigate how TMEM160 contributes to tumor growth.The expression and clinical significance of TMEM160 and PD-L1 in CRC tissues were evaluated by immunohistochemistry(IHC).

RESULTS

In our study, we made a discovery that TMEM160 interacts with PD-L1 and plays a role in stabilizing its expression within a CRC model. Furthermore, we demonstrated that TMEM160 hinders the ubiquitination-dependent degradation of PD-L1 by competing with SPOP for binding to PD-L1 in CRC cells. Regarding functionality, the absence of TMEM160 significantly inhibited the proliferation, invasion, metastasis, clonogenicity, and radioresistance of CRC cells, while simultaneously enhancing the cytotoxic effect of CD8 + T cells on tumor cells. Conversely, the upregulation of TMEM160 substantially increased these capabilities. In severely immunodeficient mice, tumor growth derived from lentiviral vector shTMEM160 cells was lower compared with that derived from shNC control cells. Furthermore, the downregulation of TMEM160 significantly restricted tumor growth in immune-competent BALB/c mice. In clinical samples from patients with CRC, we observed a strong positive correlation between TMEM160 expression and PD-L1 expression, as well as a negative correlation with CD8A expression. Importantly, patients with high TMEM160 expression exhibited a worse prognosis compared with those with low or no TMEM160 expression.

CONCLUSIONS

Our study reveals that TMEM160 inhibits the ubiquitination-dependent degradation of PD-L1 that is mediated by SPOP, thereby stabilizing PD-L1 expression to foster the malignant progress, radioresistance, and immune evasion of CRC cells. These findings suggest that TMEM160 holds potential as a target for the treatment of patients with CRC.

Pulmonary blastoma is successfully treated with immunotherapy and targeted therapy

Pulmonary blastomas (PB) are an extremely rare type of lung cancer. Currently, no standard treatment exists for PB. Immunotherapy with checkpoint inhibitors and anti-angiogenesis treatments has been an effective method for lung cancer; however, studies on PB treatment are lacking. Herein, we present a case report of successful conversion therapy with immunotherapy and targeted therapy for PB. After receiving treatment with a PD-1 inhibitor (penpulimab) and a multi-target tyrosine kinase inhibitor (anlotinib) treatment, the patient showed an impressive response and underwent a successful operation. We also summarized and reviewed literature reports on PubMed from January 1, 2000, to December 31, 2022, using the keyword "pulmonary blastoma", discussing the efficacy and specifics of chemotherapy and radiotherapy. Immunotherapy, in combination with targeted therapy, should be considered a potential therapeutic strategy for PB.

Immunotherapy for non-small cell lung cancer

Immune checkpoint inhibitors (ICI) bind to programmed cell death-1 (PD-1)/PD-1 ligand-1 (PD-L1) and Cytotoxic T-lymphocyte antigen-4 (CTLA-4), which suppress T-cell function and inhibit their inhibitory function, resulting in T-cell activation. ICI have been approved for a wide range of cancers, including malignant melanoma, renal cell carcinoma, non-small cell lung cancer, head and neck cancer, Hodgkin's disease, small-cell lung cancer, malignant pleural mesothelioma, gastric cancer, esophageal cancer, breast cancer, uterine cancer, and hepatocellular carcinoma, and the number of indications continues to grow. In addition to the treatment of advanced disease, the anti-tumor effect has been demonstrated across disease stages, from locally advanced disease to early-stage operative disease. The treatment of lung cancer is at the forefront of this trend and long-term durable responses and survival benefits in lung cancer have been exhibited that were unimaginable when cytotoxic anticancer agents were the only treatment options. However, treatment efficacy varies greatly from case to case, and no biomarkers have been developed to accurately predict efficacy. In this article, we discuss the past and future of ICI therapy for lung cancer, based on clinical and basic evidence accumulated to-date.

Perspectives on Psoriasiform Adverse Events from Immune Checkpoint Inhibitors: Lessons Learned from Our Practice

Background: New oncologic therapies, including immune checkpoint inhibitors (ICIs), have revolutionized the survival and prognosis of cancer patients. However, these therapies are often complicated by immune-related adverse effects (irAEs) that may impact quality of life and potentially limit their use. Among these adverse events are psoriasis and psoriatic arthritis that may develop de novo or flare under treatment with ICIs. Given the exceptional immune status of patients receiving ICIs, managing these conditions without interfering with the effect of the oncologic treatment may prove very challenging. Aim: To review the literature data on ICI-induced psoriasis exacerbation or development, to present our own experience, and to discuss the pathogenic mechanisms underlying this association and the optimal therapeutic approach for these patients. Case Reports: We report three cases of ICI-induced de novo psoriasis and two cases of ICI-induced psoriasis exacerbation that required systemic treatment. Oral acitretin treatment successfully controlled psoriasis lesions in three cases and allowed for the continuation of immunotherapy. Literature Review: We performed a medical literature search across several databases (PubMed, Medline, Google Scholar) using the search terms "immune checkpoint inhibitor-induced psoriasis/psoriasiform dermatitis/psoriasis arthritis". We identified and revised 80 relevant publications that reported 1102 patients with psoriasis and/or psoriasis arthritis induced or exacerbated by ICIs. We assessed the type of cancer, the therapeutic agent involved, the clinical form of psoriasis, the presence or absence of psoriatic arthritis, the personal and family history of psoriasis, the age, the gender, the time until onset or exacerbation of skin lesions, the specific treatment recommended, the need for ICI discontinuation, and the patient's outcome. Conclusions: As ICIs represent a fairly novel therapy, the association with several adverse effects is only now unraveling. Psoriasis exacerbation or onset following the initiation of immunotherapy is one such example, as more and more reports and case series are being published. Awareness of the relationship between psoriasis and treatment with ICIs, prompt recognition, and initiation of adequate skin-directed therapies are essential for the avoidance of skin lesions worsening, the need for systemic treatments that may interfere with ICIs' effects, or the discontinuation of the latter. In the absence of generally accepted guidelines, it is advisable to treat patients with severe, widespread psoriasis with drugs that do not impair the effects of immunotherapy and thus do not alter the patient's prognosis.

Immune cell networking in solid tumors: focus on macrophages and neutrophils

The tumor microenvironment is composed of tumor cells, stromal cells and leukocytes, including innate and adaptive immune cells, and represents an ecological niche that regulates tumor development and progression. In general, inflammatory cells are considered to contribute to tumor progression through various mechanisms, including the formation of an immunosuppressive microenvironment. Macrophages and neutrophils are important components of the tumor microenvironment and can act as a double-edged sword, promoting or inhibiting the development of the tumor. Targeting of the immune system is emerging as an important therapeutic strategy for cancer patients. However, the efficacy of the various immunotherapies available is still limited. Given the crucial importance of the crosstalk between macrophages and neutrophils and other immune cells in the formation of the anti-tumor immune response, targeting these interactions may represent a promising therapeutic approach against cancer. Here we will review the current knowledge of the role played by macrophages and neutrophils in cancer, focusing on their interaction with other immune cells.

Tumor-draining lymph nodes: opportunities, challenges, and future directions in colorectal cancer immunotherapy

Tumor-draining lymph nodes (TDLNs) are potential immunotherapy targets that could expand the population of patients with colorectal cancer (CRC) who may benefit from immunotherapy. Currently, pathological detection of tumor cell infiltration limits the acquisition of immune information related to the resected lymph nodes. Understanding the immune function and metastatic risk of specific stages of lymph nodes can facilitate better discussions on the removal or preservation of lymph nodes, as well as the timing of immunotherapy. This review summarized the contribution of TDLNs to CRC responses to immune checkpoint blockade therapy, local immunotherapy, adoptive cell therapy, and cancer vaccines, and discussed the significance of these findings for the development of diagnostics based on TDLNs and the potential implications for guiding immunotherapy after a definitive diagnosis. Molecular pathology and immune spectrum diagnosis of TDLNs will promote significant advances in the selection of immunotherapy options and predicting treatment efficacy.

Harnessing the innate immune system by revolutionizing macrophage-mediated cancer immunotherapy

Immunotherapy is a promising and safer alternative to conventional cancer therapies. It involves adaptive T-cell therapy, cancer vaccines, monoclonal antibodies, immune checkpoint blockade (ICB), and chimeric antigen receptor (CAR) based therapies. However, most of these modalities encounter restrictions in solid tumours owing to a dense, highly hypoxic and immune-suppressive microenvironment as well as the heterogeneity of tumour antigens. The elevated intra-tumoural pressure and mutational rates within fastgrowing solid tumours present challenges in efficient drug targeting and delivery. The tumour microenvironment is a dynamic niche infiltrated by a variety of immune cells, most of which are macrophages. Since they form a part of the innate immune system, targeting macrophages has become a plausible immunotherapeutic approach. In this review, we discuss several versatile approaches (both at pre-clinical and clinical stages) such as the direct killing of tumour-associated macrophages, reprogramming pro-tumour macrophages to anti-tumour phenotypes, inhibition of macrophage recruitment into the tumour microenvironment, novel CAR macrophages, and genetically engineered macrophages that have been devised thus far. These strategies comprise a strong and adaptable macrophage-toolkit in the ongoing fight against cancer and by understanding their significance, we may unlock the full potential of these immune cells in cancer therapy.