A PD-L2-based immune marker signature helps to predict survival in resected pancreatic ductal adenocarcinoma

Noninvasive Monitoring of Programmed Death-Ligand 2 Expression with Positron Emission Tomography using 68Ga-labeled Peptide Antagonist in Preclinical and Exploratory Human Studies

While the expression of programmed death ligand-1 (PD-L1) is associated with response to immune therapy, PD-L1-negative patients may still benefit from immune treatment. Programmed death ligand-2 (PD-L2), another crucial immune checkpoint molecule interacting with PD-1, correlates with the efficacy of various tumor immune therapies. This study investigates the expression of PD-L2 in non-small cell lung cancer (NSCLC) patients following anti-PD-1 therapy and its predictive value for clinical survival outcomes. Additionally, we explore the noninvasive, real-time, and dynamic quantitative analysis potential of PD-L2 positron emission tomography (PET) imaging in transplanted tumors. We utilized [68Ga]Ga-labeled peptide HN11-1 for PD-L2 PET imaging. The results indicate a higher response rate to anti-PD-1 therapy in patients positive for both PD-L1 and PD-L2, with PD-L2 status independently predicting progression-free survival (PFS) with pembrolizumab treatment. Furthermore, [68Ga]Ga-HN11-1 PET imaging demonstrates specificity in assessing PD-L2 status. Overall, we confirm the correlation between high PD-L2 expression and favorable PFS in NSCLC patients post anti-PD-1 therapy and highlight the promising potential of [68Ga]Ga-HN11-1 as a specific tracer for PD-L2 in preclinical and initial human trials.

Construction and preclinical evaluation of a 124I-labelled bispecific antibody targeting PD-L1 and PD-L2

PURPOSE

NB12 is a bispecific antibody that consists of two anti-programmed cell death-ligand 1 (PD-L1) nanobodies and two anti-programmed cell death-ligand 2 (PD-L2) nanobodies. The aim of this study was to design a novel tracer, [124I]I-NB12, targeting PD-L1/2 and perform preclinical evaluations to dynamically monitor PD-L1/2 expression for determining cancer patient responsiveness to ICI therapy.

METHODS

NB12 was labelled with the radionuclide 124I at room temperature (RT). An in vitro binding assay was performed to assess the affinity of [124I]I-NB12 for PD-L1 and PD-L2. Cellular uptake, pharmacokinetic, and biodistribution experiments were performed to evaluate the biological properties. Micro-PET/CT imaging with [124I]I-NB12 was conducted at different time points. Immunohistochemical and haematoxylin and eosin (HE) staining experiments were carried out using tumour tissues. Routine blood, biochemical indices and major organ pathology were used to evaluate the biosafety of the tracers.

RESULTS

The radiochemical yield of [124I]I-NB12 was 84.62 ± 3.90%, and the radiochemical purity (RCP) was greater than 99%. [124I]I-NB12 had a high affinity for the PD-L1 (Kd = 19.82 nM) and PD-L2 (Kd = 2.93 nM). Cellular uptake experiments confirmed that the uptake of [124I]I-NB12 by A549-PDL1/2 cells was greater than that by A549 cells. The half-lives of the distribution phase and elimination phase were 0.26 h and 4.08 h, respectively. Micro-PET/CT showed significant [124I]I-NB12 uptake in the tumour region of A549-PDL1/2 tumour-bearing mice compared with A549 tumour-bearing mice 24 h postinjection. Immunohistochemical and HE staining experiments confirmed that tumour-bearing mice was successfully constructed.

CONCLUSION

We constructed a bispecific antibody that targets PD-L1 and PD-L2, namely, [124I]I-NB12. Biological evaluation revealed its specificity and affinity for PD-L1/2, and micro-PET/CT confirmed the feasibility of visualizing tumour PD-L1/2 in vivo. Using [124I]I-NB12 may be a promising strategy for identifying cancer patients that can potentially benefit from ICI therapy.

TGFβ2 Promotes the Construction of Fibrotic and Immunosuppressive Tumor Microenvironment in Pancreatic Adenocarcinoma: A Comprehensive Analysis

Pancreatic adenocarcinoma (PAAD) was characterized by dense fibrotic stroma and immunosuppressive tumor microenvironment (TME). TGFβ signaling pathways are highly activated in human cancers. However, the role of TGFβ2 in TME of PAAD remains to be elucidated. In this study, we showed that TGFβ2 was expressed at a relatively high level in PAAD tissues or cancer cells. Moreover, its high expression predicted unfavorable prognosis. In PAAD, gene set enrichment analysis showed that TGFβ2 correlated positively with leukocyte transendothelial migration, but negatively with aerobic metabolism, including oxidative phosphorylation. Results in Tumor and Immune System Interaction Database showed that TGFβ2 correlated with the infiltration of tumor-associated macrophages (TAMs), which could be attributed to that TGFβ2 promote CCL2 expression in PAAD. Moreover, correlation analysis showed that TGFβ2 could trigger cancer-associated fibroblasts (CAFs) activation in PAAD. The drug sensitivity analysis may indicate that patients with TGFβ2 high expression have higher sensitivity to chemotherapeutics, but the sensitivity to targeted drugs is still controversial. TGFβ2 could promote expansion of CAFs and infiltration of TAMs, thus participating in the construction of a fibrotic and immunosuppressive TME in PAAD. Targeting TGFβ2 could be a promising therapeutic approach, which needs to be elucidated by clinical and experimental evidences.

PD-L2 mediates tobacco smoking-induced recruitment of regulatory T cells via the RGMB/NFκB/CCL20 cascade

Programmed cell death ligand 2 (PD-L2), a ligand for the receptor programmed cell death 1 (PD-1), has an identity of 34% with its twin ligand PD-L1 and exhibits higher binding affinity with PD-1 than PD-L1. However, the role of PD-L2 in non-small cell lung cancer (NSCLC) progression, especially tobacco-induced cancer progression, has not been fully understood. Here, we found that PD-L2 promoted tumor growth in murine models with recruitment of regulatory T cells (Tregs). In patients with NSCLC, PD-L2 expression level in tumor samples was higher than in counterpart normal controls and was positively associated with patients' response to anti-PD-1 treatment. Mechanismly, PD-L2 bound its receptor Repulsive guidance molecule B (RGMB) on cancer cells and activated extracellular signal-regulated kinase (Erk) and nuclear factor κB (NFκB), leading to increased production of chemokine CCL20, which recruited Tregs and contributed to NSCLC progression. Consistently, knockdown of RGMB or NFκB p65 inhibited PD-L2-induced CCL20 production, and silencing of PD-L2 repressed Treg recruitment by NSCLC cells. Furthermore, cigarette smoke and carcinogen benzo(a)pyrene (BaP) upregulated PD-L2 in lung epithelial cells via aryl hydrocarbon receptor (AhR)-mediated transcription activation, whose deficiency markedly suppressed BaP-induced PD-L2 upregulation. These results suggest that PD-L2 mediates tobacco-induced recruitment of Tregs via the RGMB/NFκB/CCL20 cascade, and targeting this pathway might have therapeutic potentials in NSCLC.

Immune cells and checkpoints in pancreatic adenocarcinoma: Association with clinical and pathological characteristics

INTRODUCTION

Pancreatic adenocarcinoma is an extremely aggressive neoplasm, with many challenges to be overcome in order to achieve a truly effective treatment. It is characterized by a mostly immunosuppressed environment, with dysfunctional immune cells and active immunoinhibitory pathways that favor tumor evasion and progression. Thus, the study and understanding of the tumor microenvironment and the various cells subtypes and their functional capacities are essential to achieve more effective treatments, especially with the use of new immunotherapeutics.

METHODS

Seventy cases of pancreatic adenocarcinoma divided into two groups 43 with resectable disease and 27 with unresectable disease were analyzed using immunohistochemical methods regarding the expression of programmed cell death ligand 1 (PD-L1), programmed cell death ligand 2 (PD-L2), and human leukocyte antigen G (HLA-G) molecules as well as the populations of CD4+ and CD8+ T lymphocytes, regulatory T cells (Tregs), and M2 macrophages (MM2). Several statistical tests, including multivariate analyses, were performed to examine how those immune cells and immunoinhibitory molecules impact the evolution and prognosis of pancreatic adenocarcinoma.

RESULTS

CD8+ T lymphocytes and M2 macrophages predominated in the group operated on, and PD-L2 expression predominated in the unresectable group. PD-L2 was associated with T stage, lymph node metastasis, and clinical staging, while in survival analysis, PD-L2 and HLA-G were associated with a shorter survival. In the inoperable cases, Tregs cells, MM2, PD-L1, PD-L2, and HLA-G were positively correlated.

CONCLUSIONS

PD-L2 and HLA-G expression correlated with worse survival in the cases studied. Tumor microenvironment was characterized by a tolerant and immunosuppressed pattern, mainly in unresectable lesions, where a broad positive influence was observed between immunoinhibitory cells and immune checkpoint proteins expressed by tumor cells.

Prognostic heterogeneity of Ki67 in non-small cell lung cancer: A comprehensive reappraisal on immunohistochemistry and transcriptional data

In the present study, the debatable prognostic value of Ki67 in patients with non-small cell lung cancer (NSCLC) was attributed to the heterogeneity between lung adenocarcinoma (LUAD) and lung squamous carcinoma (LUSC). Based on meta-analyses of 29 studies, a retrospective immunohistochemical cohort of 1479 patients from our center, eight transcriptional datasets and a single-cell datasets with 40 patients, we found that high Ki67 expression suggests a poor outcome in LUAD, but conversely, low Ki67 expression indicates worse prognosis in LUSC. Furthermore, low proliferation in LUSC is associated with higher metastatic capacity, which is related to the stronger epithelial-mesenchymal transition potential, immunosuppressive microenvironment and angiogenesis. Finally, nomogram model incorporating clinical risk factors and Ki67 expression outperformed the basic clinical model for the accurate prognostic prediction of LUSC. With the largest prognostic assessment of Ki67 from protein to mRNA level, our study highlights that Ki67 also has an important prognostic value in NSCLC, but separate evaluation of LUAD and LUSC is necessary to provide more valuable information for clinical decision-making in NSCLC.

Analysis of PD-L1 promoter methylation combined with immunogenic context in pancreatic ductal adenocarcinoma

Despite the successful application of programmed cell death ligand 1 (PD-L1)-blocking strategies in some types of cancers and well-established prognostic indicators in pancreatic ductal adenocarcinoma (PDAC), the biological and clinical implications of the methylation status of PD-L1/PD-L2 in PDAC remain largely unknown. Therefore, this study aimed to explore the biological role of PD-L1/PD-L2 methylation and its association with clinicopathological features, clinical outcomes, and the immune microenvironment by analyzing the data on PD-L1/PD-L2 methylation and mRNA expression in PDAC cohorts obtained from the Cancer Genome Atlas and International Cancer Genome Consortium. The correlation between PD-L1 promoter methylation and PD-L1 expression and survival was further validated in an independent validation cohort (Peking Union Medical College Hospital [PUMCH] cohort) using pyrosequencing and immunohistochemistry. These results demonstrated that hypomethylation of the PD-L1 promoter was strongly associated with upregulated PD-L1 expression and shorter overall survival in PDAC. Multivariate Cox regression analyses revealed that the PD-L1 promoter methylation was an independent prognostic factor. PD-L1 promoter hypomethylation and high expression were related to aggressive clinical phenotypes. Moreover, both PD-L1 and PD-L2 methylation correlated with immune cell infiltration and the expression of immune checkpoint genes. PD-L1 promoter methylation status was further validated as an independent prognostic biomarker in patients with PDAC using the PUMCH cohort. The prognostic significance of PD-L1 promoter methylation was more discriminative in tumors with perineural/lymphovascular invasion and distant metastasis than in those without perineural/lymphovascular invasion and distant metastasis. In summary, the methylation status of the PD-L1 promoter is a promising biomarker for survival outcomes, immune infiltration, and the potential immune benefits of immunotherapy in PDAC.

Programmed cell death-ligand 2: new insights in cancer

Immunotherapy has revolutionized cancer treatment, with the anti-PD-1/PD-L1 axis therapy demonstrating significant clinical efficacy across various tumor types. However, it should be noted that this therapy is not universally effective for all PD-L1-positive patients, highlighting the need to expedite research on the second ligand of PD-1, known as Programmed Cell Death Receptor Ligand 2 (PD-L2). As an immune checkpoint molecule, PD-L2 was reported to be associated with patient's prognosis and plays a pivotal role in cancer cell immune escape. An in-depth understanding of the regulatory process of PD-L2 expression may stratify patients to benefit from anti-PD-1 immunotherapy. Our review focuses on exploring PD-L2 expression in different tumors, its correlation with prognosis, regulatory factors, and the interplay between PD-L2 and tumor treatment, which may provide a notable avenue in developing immune combination therapy and improving the clinical efficacy of anti-PD-1 therapies.

Comparison of Clinical Trial Results of the Recently Approved Immunotherapeutic Drugs for Advanced Biliary Tract Cancers

The recently approved immunotherapeutic drugs are Keytruda (pembrolizumab) and Imfinzi (durvalumab) for advanced biliary tract cancers that inhibit PD-1 receptor and PD-L1 ligand, respectively. In this perspective, the results of the two clinical trials, i.e., TOPAZ-1 (NCT03875235) and KEYNOTE-966 (NCT04003636), are critically appraised, compared, and discussed to assess the benefits of these two drugs in the context of the treatment of advanced biliary tract cancers with a focus on PD-L1 status and MIS (microsatellite instability) status and therapy responsiveness in the subgroups. Analyzing the PD-L2 status in biliary tract cancer patients can aid in assessing the prognostic value of PD-L2 expression in determining the clinical response and this may aid in appropriate patient stratification.

Inhibitory checkpoint molecule mRNA expression in canine soft tissue sarcoma

Canine soft tissue sarcomas (STS) are common neoplasms and considered immune deserts. Tumour infiltrating lymphocytes are sparse in STS and, when present, tend to organize around blood vessels or at the periphery of the neoplasm. This pattern is associated with an immunosuppressive tumour microenvironment linked to overexpression of molecules of the PD-axis. PD-1, PD-L1 and PD-L2 expression correlates with malignancy and poor prognosis in other neoplasms in humans and dogs, but little is known about their role in canine STS, their relationship to tumour grade, and how different therapies affect expression. The objective of this study was to evaluate the expression of checkpoint molecules across STS tumour grades and after tumour ablation treatment. Gene expression analysis was performed by reverse-transcriptase real-time quantitative PCR in soft tissue sarcomas that underwent histotripsy and from histologic specimens of STS from the Virginia Tech Animal Laboratory Services archives. The expression of PD-1, PD-L1 and PD-L2 was detected in untreated STS tissue representing grades 1, 2, and 3. Numerically decreased expression of all markers was observed in tissue sampled from the treatment interface relative to untreated areas of the tumour. The relatively lower expression of these checkpoint molecules at the periphery of the treated area may be related to liquefactive necrosis induced by the histotripsy treatment, and would potentially allow TILs to infiltrate the tumour. Relative increases of these checkpoint molecules in tumours of a higher grade and alongside immune cell infiltration are consistent with previous reports that associate their expression with malignancy.

An alternatively spliced PD-L1 isoform PD-L1∆3, and PD-L2 expression in breast cancers: implications for eligibility scoring and immunotherapy response

Targeting PD-1/PD-L1 has shown substantial therapeutic response and unprecedented long-term durable responses in the clinic. However, several challenges persist, encompassing the prediction of treatment effectiveness and patient responses, the emergence of treatment resistance, and the necessity for additional biomarkers. Consequently, we comprehensively explored the often-overlooked isoforms of crucial immunotherapy players, leveraging transcriptomic analysis, structural modeling, and immunohistochemistry (IHC) data. Our investigation has led to the identification of an alternatively spliced isoform of PD-L1 that lacks exon 3 (PD-L1∆3) and the IgV domain required to interact with PD-1. PD-L1∆3 is expressed more than the canonical isoform in a subset of breast cancers and other TCGA tumors. Using the deep learning-based protein modeling tool AlphaFold2, we show the lack of a possible interaction between PD-L1∆3 and PD-1. In addition, we present data on the expression of an additional ligand for PD-1, PD-L2. PD-L2 expression is widespread and positively correlates with PD-L1 levels in breast and other tumors. We report enriched epithelial-mesenchymal transition (EMT) signature in high PD-L2 transcript expressing (PD-L2 > PD-L1) tumors in all breast cancer subtypes, highlighting potential crosstalk between EMT and immune evasion. Notably, the estrogen gene signature is downregulated in ER + breast tumors with high PD-L2. The data on PD-L2 IHC positivity but PD-L1 negativity in breast tumors, together with our results on PD-L1∆3, highlight the need to utilize PD-L2 and PD-L1 isoform-specific antibodies for staining patient tissue sections to offer a more precise prediction of the outcomes of PD-1/PD-L1 immunotherapy.

Development of an Albumin-Masked mutPD-1Ig as a Tumor Lesion-Selective Immune Checkpoint Inhibitor

The antitumor effects elicited by immune checkpoint inhibitors (ICIs) have transformed cancer treatments. However, severe immune-related adverse events (irAEs) resulting from these treatments have restricted the application of ICIs. To overcome the adverse events, we developed a tumor lesion-selective pro-PD-1Ig that is activated by proteases overexpressed in tumors. We genetically linked albumin to the N-terminus of a modified PD-1Ig (termed mutPD-1Ig hereafter) via an MMP substrate sequence to form Alb-hinge-mutPD-1Ig. We demonstrate that the binding activity of nondigested Alb-hinge-mutPD-1Ig is approximately 11-folds lower than mutPD-1Ig. However, digestion by type IV collagenase restored the binding activity of Alb-hinge-mutPD-1Ig to a level comparable to that of native mutPD-1Ig. In order to enhance the masking efficiency of Alb-mutPD-1Ig, we simulated the effects of diverse MMP substrate linkers for connecting albumin and PD-1 at various starting positions by bioinformatics tools. Our validation experiments indicate Alb-hinge-mutPD-1Ig displayed the best masking efficiency among all simulated constructs. Our study suggests that albumin may be best applicable to mask a target protein whose binding motif is centralized and in the proximity of the N-terminus of the protein.

Expression of PD-L1 and VISTA in Intraductal Papillary Mucinous Neoplasm With Associated Invasive Carcinoma of the Pancreas

Early detection and treatment of invasive carcinoma arising in association with intraductal papillary mucinous neoplasm (IPMN), which is biologically and (epi)genetically distinct from conventional pancreatic ductal adenocarcinoma, provide an opportunity to improve the prognosis of this lethal disease. Despite the successful application of programmed death (ligand) 1 (PD-[L]1)-blocking strategies in numerous cancers, the immune microenvironment of IPMN with associated invasive carcinoma remains elusive. Here, we investigated CD8+ T cells, CD68+ macrophages, PD-L1, and V-domain immunoglobulin suppressor of T-cell activation (VISTA) in 60 patients with IPMN with associated invasive carcinoma using immunohistochemistry, explored their correlations with clinicopathologic variables and prognosis, and compared them with those in 76 patients with IPMN without invasive carcinoma (60 low-grade and 16 high-grade lesions). Using antibodies against CD8, CD68, and VISTA, we evaluated tumor-infiltrating immune cells in 5 high-power fields (×400) and calculated the corresponding mean counts. PD-L1 with a combined positive score of ≥1 was regarded as positive, and VISTA expression on tumor cells (TCs) was deemed positive when ≥1% of TCs showed membranous/cytoplasmic staining. A reduction of CD8+ T cells and an increase of macrophages were observed during carcinogenesis. Positive PD-L1 combined positive score and VISTA expression on TCs were 13% and 11% in the intraductal component of IPMN with associated invasive carcinoma, 15% and 12% in the associated invasive carcinoma, and 6% and 4% in IPMN without an invasive carcinoma, respectively. Interestingly, the PD-L1 positivity rate was the highest in a subset of associated invasive carcinomas (predominantly gastric-type-derived) and was associated with higher counts of CD8+ T cells, macrophages, and VISTA+ immune cells. Accumulation of VISTA+ immune cells was observed in the intraductal component of IPMN with associated invasive carcinoma compared with that of low-grade IPMN, whereas in intestinal-type IPMN with associated invasive carcinoma, the number of these cells decreased during the transition from the intraductal component to the associated invasive carcinoma. Survival analysis revealed that a higher number of macrophages predicted poorer prognosis. In conclusion, our results might help in individualized immunotherapeutic strategies for these patients.

Tissue-Resident Memory T Cells in Pancreatic Ductal Adenocarcinoma Coexpress PD-1 and TIGIT and Functional Inhibition Is Reversible by Dual Antibody Blockade

Pancreatic ductal adenocarcinoma (PDAC) has a poor clinical outlook. Responses to immune checkpoint blockade are suboptimal and a much more detailed understanding of the tumor immune microenvironment is needed if this situation is to be improved. Here, we characterized tumor-infiltrating T-cell populations in patients with PDAC using cytometry by time of flight (CyTOF) and single-cell RNA sequencing. T cells were the predominant immune cell subset observed within tumors. Over 30% of CD4+ T cells expressed a CCR6+CD161+ Th17 phenotype and 17% displayed an activated regulatory T-cell profile. Large populations of CD8+ tissue-resident memory (TRM) T cells were also present and expressed high levels of programmed cell death protein 1 (PD-1) and TIGIT. A population of putative tumor-reactive CD103+CD39+ T cells was also observed within the CD8+ tumor-infiltrating lymphocytes population. The expression of PD-1 ligands was limited largely to hemopoietic cells whilst TIGIT ligands were expressed widely within the tumor microenvironment. Programmed death-ligand 1 and CD155 were expressed within the T-cell area of ectopic lymphoid structures and colocalized with PD-1+TIGIT+ CD8+ T cells. Combinatorial anti-PD-1 and TIGIT blockade enhanced IFNγ secretion and proliferation of T cells in the presence of PD-1 and TIGIT ligands. As such, we showed that the PDAC microenvironment is characterized by the presence of substantial populations of TRM cells with an exhausted PD-1+TIGIT+ phenotype where dual checkpoint receptor blockade represents a promising avenue for future immunotherapy.

Pan-cancer analysis identifies PD-L2 as a tumor promotor in the tumor microenvironment

BACKGROUND

Programmed cell death protein 1 (PD-1) receptor has two ligands,programmed death-ligand 1 (PD-L1) and PD-L2. When compared with PD-L1, PD-L2 has not received much attention, and its role remains unclear.

METHODS

The expression profiles of pdcd1lg2 (PD-L2-encoding gene) mRNA and PD-L2 protein were analyzed using TCGA, ICGC, and HPA databases. Kaplan-Meier and Cox regression analyses were used to assess the prognostic significance of PD-L2. We used GSEA, Spearman's correlation analysis and PPI network to explore the biological functions of PD-L2. PD-L2-associated immune cell infiltration was evaluated using the ESTIMATE algorithm and TIMER 2.0. The expressions of PD-L2 in tumor-associated macrophages (TAMs) in human colon cancer samples, and in mice in an immunocompetent syngeneic setting were verified using scRNA-seq datasets, multiplex immunofluorescence staining, and flow cytometry. After fluorescence-activated cell sorting, flow cytometry and qRT-PCR and transwell and colony formation assays were used to evaluate the phenotype and functions of PD-L2+TAMs. Immune checkpoint inhibitors (ICIs) therapy prediction analysis was performed using TIDE and TISMO. Last, a series of targeted small-molecule drugs with promising therapeutic effects were predicted using the GSCA platform.

RESULTS

PD-L2 was expressed in all the common human cancer types and deteriorated outcomes in multiple cancers. PPI network and Spearman's correlation analysis revealed that PD-L2 was closely associated with many immune molecules. Moreover, both GSEA results of KEGG pathways and GSEA results for Reactome analysis indicated that PD-L2 expression played an important role in cancer immune response. Further analysis showed that PD-L2 expression was strongly associated with the infiltration of immune cells in tumor tissue in almost all cancer types, among which macrophages were the most positively associated with PD-L2 in colon cancer. According to the results mentioned above, we verified the expression of PD-L2 in TAMs in colon cancer and found that PD-L2+TAMs population was not static. Additionally, PD-L2+TAMs exhibited protumor M2 phenotype and increased the migration, invasion, and proliferative capacity of colon cancer cells. Furthermore, PD-L2 had a substantial predictive value for ICIs therapy cohorts.

CONCLUSION

PD-L2 in the TME, especially expressed on TAMs, could be applied as a potential therapeutic target.

Exploration of 68Ga-labelled prostate-specific membrane antigen-11 PET/CT parameters for identifying PBRM1 status in primary clear cell renal cell carcinoma

AIM

To investigate the predictive value of ⁶⁸Ga-labelled prostate-specific membrane antigen-11 (⁶⁸Ga-PSMA-11) integrated positron-emission tomography (PET)/computed tomography (CT) in PBRM1-deficient clear cell renal cell carcinoma (ccRCC).

MATERIALS AND METHODS

A total of 41 patients with ccRCC, were enrolled retrospectively and underwent ⁶⁸Ga-PSMA-11 PET/CT preoperatively. Radiological parameters, including CT attenuation value and maximum standard uptake value (SUVmax), were derived. Immunohistochemical and multiple immunofluorescences staining were performed to evaluate the PBRM1 status and immune response. The predictive value of imaging factors was analysed using a receiver operator characteristic curve analysis. Univariate and multivariate logistic regression analyses were used to investigate the relationship between clinical and radiological variables and PBRM1 status.

RESULTS

A total of 41 patients were included in this study, with 14 patients having PBRM1-deficient status. The tumour diameter on imaging and SUVmax differed significantly in patients with different PBRM1 expression statuses and no difference in CT attenuation was identified. Univariate and multivariate logistic regression analyses showed SUVmax was an obvious predictor for identification of PBRM1-deficient tumours. In addition, PBRM1-deficient tumours tended to be accompanied by greater cytotoxic T-cell infiltration, although most of them were in an exhausted state.

CONCLUSIONS

⁶⁸Ga-PSMA-11 PET/CT could be used to discriminate invasive PBRM1-deficient ccRCC.

Radiomic Analysis Based on Magnetic Resonance Imaging for Predicting PD-L2 Expression in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the sixth most common malignant tumour and the third leading cause of cancer death in the world. The emerging field of radiomics involves extracting many clinical image features that cannot be recognized by the human eye to provide information for precise treatment decision making. Radiomics has shown its importance in HCC identification, histological grading, microvascular invasion (MVI) status, treatment response, and prognosis, but there is no report on the preoperative prediction of programmed death ligand-2 (PD-L2) expression in HCC. The purpose of this study was to investigate the value of MRI radiomic features for the non-invasive prediction of immunotherapy target PD-L2 expression in hepatocellular carcinoma (HCC). A total of 108 patients with HCC confirmed by pathology were retrospectively analysed. Immunohistochemical analysis was used to evaluate the expression level of PD-L2. 3D-Slicer software was used to manually delineate volumes of interest (VOIs) and extract radiomic features on preoperative T2-weighted, arterial-phase, and portal venous-phase MR images. Least absolute shrinkage and selection operator (LASSO) was performed to find the best radiomic features. Multivariable logistic regression models were constructed and validated using fivefold cross-validation. The area under the receiver characteristic curve (AUC) was used to evaluate the predictive performance of each model. The results show that among the 108 cases of HCC, 50 cases had high PD-L2 expression, and 58 cases had low PD-L2 expression. Radiomic features correlated with PD-L2 expression. The T2-weighted, arterial-phase, and portal venous-phase and combined MRI radiomics models showed AUCs of 0.789 (95% CI: 0.702-0.875), 0.727 (95% CI: 0.632-0.823), 0.770 (95% CI: 0.682-0.875), and 0.871 (95% CI: 0.803-0.939), respectively. The combined model showed the best performance. The results of this study suggest that prediction based on the radiomic characteristics of MRI could noninvasively predict the expression of PD-L2 in HCC before surgery and provide a reference for the selection of immune checkpoint blockade therapy.

Systematic Analysis of Molecular Subtypes Based on the Expression Profile of Immune-Related Genes in Pancreatic Cancer

Immunotherapy has a good therapeutic effect and provides a new approach for cancer treatment. However, only limited studies have focused on the use of molecular typing to construct an immune characteristic index for gene expression in pancreatic adenocarcinoma (PAAD) and to assess the effectiveness of immunotherapy in patients with PAAD. Clinical follow-up data and gene expression profile of PAAD patients were retrieved from The Cancer Genome Atlas (TCGA) database. Based on 184 immune features, molecular subtypes of pancreatic cancer were found by the "ConsensusClusterPlus" package, and the association between clinical features and immune cell subtype distribution was analysed. In addition, the relationship between the proportion of immune subtypes and the expression of immune checkpoints was analysed. The CIBERSORT algorithm was introduced to evaluate the immune scores of different molecular subtypes. We used the tumor immune dysfunction and exclusion (TIDE) algorithm to assess the potential clinical effect of immunotherapy interventions on single-molecule subtypes. In addition, the oxidative stress index was constructed by linear discriminant analysis DNA (LDA), and weighted correlation network analysis was performed to identify the core module of the index and its characteristic genes. Expression of hub genes was verified by immunohistochemical analysis in an independent PAAD cohort. Pancreatic cancer is divided into three molecular subtypes (IS1, IS2, and IS3), with significant differences in prognosis between multiple cohorts. Expression of immune checkpoint-associated genes was significantly reduced in IS3 and higher in IS1 and IS2, suggesting that the three subgroups have different responsiveness to immunotherapy interventions. The results of the CIBERSORT analysis showed that IS1 exhibited the highest levels of immune infiltration, whereas the results of the TIDE analysis showed that the T-cell dysfunction score of IS1 was higher than that of IS2 and IS3. Furthermore, IS3 was found to be more sensitive to 5-FU and to have a higher immune signature index than IS1 and IS2. Based on WGCNA analysis, 10 potential gene markers were identified, and their expression at the protein level was verified by immunohistochemical analysis. Specific molecular expression patterns in pancreatic cancer can predict the efficacy of immunotherapy and influence the prognosis of patients.

Evolving landscape of PD-L2: bring new light to checkpoint immunotherapy

Immune checkpoint blockade therapy targeting programmed cell death protein 1 (PD-1) has revolutionized the landscape of multiple human cancer types, including head and neck squamous carcinoma (HNSCC). Programmed death ligand-2 (PD-L2), a PD-1 ligand, mediates cancer cell immune escape (or tolerance independent of PD-L1) and predicts poor prognosis of patients with HNSCC. Therefore, an in-depth understanding of the regulatory process of PD-L2 expression may stratify patients with HNSCC to benefit from anti-PD-1 immunotherapy. In this review, we summarised the PD-L2 expression and its immune-dependent and independent functions in HNSCC and other solid tumours. We focused on recent findings on the mechanisms that regulate PD-L2 at the genomic, transcriptional, post-transcriptional, translational, and post-translational levels, also in intercellular communication of tumour microenvironment (TME). We also discussed the prospects of using small molecular agents indirectly targeting PD-L2 in cancer therapy. These findings may provide a notable avenue in developing novel and effective PD-L2-targeted therapeutic strategies for immune combination therapy and uncovering biomarkers that improve the clinical efficacy of anti-PD-1 therapies.

B7 Family Members in Pancreatic Ductal Adenocarcinoma: Attractive Targets for Cancer Immunotherapy

Pancreatic ductal adenocarcinoma (PDAC) is one of the deadliest cancers, with a five-year survival rate of approximately 5-10%. The immune checkpoint blockade represented by PD-1/PD-L1 inhibitors has been effective in a variety of solid tumors but has had little clinical response in pancreatic cancer patients. The unique suppressive immune microenvironment is the primary reason for this outcome, and it is essential to identify key targets to remodel the immune microenvironment. Some B7 family immune checkpoints, particularly PD-L1, PD-L2, B7-H3, B7-H4, VISTA and HHLA2, have been identified as playing a significant role in the control of tumor immune responses. This paper provides a comprehensive overview of the recent research progress of some members of the B7 family in pancreatic cancer, which revealed that they can be involved in tumor progression through immune-dependent and non-immune-dependent pathways, highlighting the mechanisms of their involvement in tumor immune escape and assessing the prospects of their clinical application. Targeting B7 family immune checkpoints is expected to result in novel immunotherapeutic treatments for patients with pancreatic cancer.

NEUROD1 predicts better prognosis in pancreatic cancer revealed by a TILs-based prognostic signature

It has been well-defined that tumor-infiltrating lymphocytes (TILs) play critical roles in pancreatic cancer (PaCa) progression. This research aimed to comprehensively explore the composition of TILs in PaCa and their potential clinical significance. A total of 178 samples from the TCGA and 63 samples from the GSE57495 dataset were enrolled in our study. ImmuCellAI was applied to calculate the infiltrating abundance of 24 immune cell types in PaCa and further survival analysis revealed the prognostic values of TILs in PaCa. Moreover, the Hallmark enticement analysis of differentially expressed genes (DEGs) between low- and high-risk groups was performed as well. Immunohistochemistry staining was used to evaluate NEUROD1 expression. As result, different kinds of TILs had distinct infiltrating features. In addition, Specific TILs subsets had notable prognostic values in PaCa. We further established a 6-TILs signature to assess the prognosis of PaCa patients. Kaplan-Meier and Cox regression analyses both suggested the significant prognostic value of the signature in PaCa. Based on the prognostic signature, we screened a great deal of potential prognostic biomarkers and successfully validated NEUROD1 as a novel prognostic biomarker in PaCa. Overall, the current study illuminated the immune cells infiltrating the landscape in PaCa and identified a TILs-dependent signature and NEUROD1 for prognostic prediction in PaCa patients.

Clinical Value of the PD-1/PD-L1/PD-L2 Pathway in Patients Suffering from Endometriosis

The interaction between dendritic cells (DCs) and T cells mediated by the programmed cell death 1 (PD-1)/programmed cell death ligand 1 (PD-L1)/programmed cell death ligand 2 (PD-L2) pathway is the most important point in regulating immunological tolerance and autoimmunity. Disturbances in the quantity, maturity, and activity of DCs may be involved in the implantation and growth of endometrial tissue outside the uterus in endometriosis (EMS). However, little is known about the role of the immune checkpoint pathways in EMS. In our study, we examined the expression of PD-L1/PD-L2 on myeloid DCs (mDCs) and plasmacytoid DCs (pDCs) in the peripheral blood (PB) and peritoneal fluid (PF) of both EMS patients (n = 72) and healthy subjects (n = 20) via flow cytometry. The concentration of soluble PD-L1 and PD-L2 in the plasma and PF of EMS patients and the control group were determined using ELISA. We demonstrated an elevated percentage of mDCs, mDCs and pDCs with the PD-L1or PD-L2 expression, and a higher concentration of the soluble forms of PD-L1 and PD-L2 in the PF than in the plasma of EMS patients. We conclude that the peritoneal cavity environment and the PD-1/PD-L1/PD-L2 axis may play an important role in the modulation of immune response and the development and/or progression of EMS.

Prognostic value of PD-1, PD-L1 and PD-L2 deserves attention in head and neck cancer

Head and neck cancer has high heterogeneity with poor prognosis, and emerging researches have been focusing on the prognostic markers of head and neck cancer. PD-L1 expression is an important basis for strategies of immunosuppressive treatment, but whether it has prognostic value is still controversial. Although meta-analysis on PD-L1 expression versus head and neck cancer prognosis has been performed, the conclusions are controversial. Since PD-L1 and PD-L2 are two receptors for PD-1, here we summarize and analyze the different prognostic values of PD-1, PD-L1, and PD-L2 in head and neck cancer in the context of different cell types, tissue localization and protein forms. We propose that for head and neck cancer, the risk warning value of PD-1/PD-L1 expression in precancerous lesions is worthy of attention, and the prognostic value of PD-L1 expression at different subcellular levels as well as the judgment convenience of prognostic value of PD-1, PD-L1, PD-L2 should be fully considered. The PD-L1 evaluation systems established based on immune checkpoint inhibitors (ICIs) are not fully suitable for the evaluation of PD-L1 prognosis in head and neck cancer. It is necessary to establish a new PD-L1 evaluation system based on the prognosis for further explorations. The prognostic value of PD-L1, PD-L2 expression in head and neck cancer may be different for early-stage and late-stage samples, and further stratification is required.

Tumor-infiltrating lymphocyte: features and prognosis of lymphocytes infiltration on colorectal cancer

Tumor-infiltrating lymphocytes (TILs) are vital elements of the tumor microenvironment (TME), and the anti-tumor activity of TILs on colorectal cancer (CRC) has been a topic of concern. However, the characteristics and prognosis of the various types of lymphocyte infiltration in CRC have not been fully explained. Our study aimed to identify distinct features and prognosis of TILs. We integrated multiple-cohort databases to illustrate the features, proportions, and prognosis of TILs on CRC. We found that macrophages were significantly enriched in CRC. When we used the scRNA-seq database to further evaluate the proportion of TILs, we noticed markedly higher numbers of CD4 + T cell, B cell, and CD8 + T cell in four Gene Expression Omnibus Series (GSE) CRC cohorts. Interestingly, we found that the infiltrating level of TIL subgroups from highest to lowest is always dendritic cells, CD8 + T cells, CD4 + T cells, neutrophils, B cells, and macrophages; the proportion of infiltration is largely constant regardless of mutations in specific genes or somatic copy number variation (sCNV). In addition, the data corroborated that CD4+ TILs and CD8+ TILs have certain application values in the prognosis of CRCs, and age negatively related to CD8+ TILs and B plasma infiltration. Finally, patients with CRC who are older than 70 years have a better response to immune-checkpoint blockade.

PD-L1 and PD-L2 expression in pancreatic ductal adenocarcinoma and their correlation with immune infiltrates and DNA damage response molecules

Immunotherapy targeting programmed cell death‐1 (PD‐1) has considerably improved the prognosis of patients with advanced cancers; however, its efficacy in the treatment of pancreatic ductal adenocarcinoma (PDAC) is unfavourable. To address the issue of PDAC immunotherapy, we investigated the expression of two PD‐1 ligands, PD‐L1 and PD‐L2, in PDAC, analysed their role in survival, and explored their correlation with clinicopathological features, immune infiltration, and DNA damage response molecules. Immunohistochemistry was performed on 291 surgically resected PDAC samples. In tumour cells (TCs) and immune cells (ICs), the positivity of PD‐L1 expression was 30 and 20% and that of PD‐L2 expression was 40 and 20%, respectively. Moreover, PD‐L1 expression on TCs correlated with its expression on ICs (p < 0.0001); a similar result was observed for PD‐L2 (p < 0.0001). Nonetheless, no correlation was observed between PD‐L1 and PD‐L2 expression. Positive PD‐L1 expression on TCs was related to N1 stage (p = 0.011) and AJCC II stage (p = 0.002), whereas positive PD‐L2 expression on TCs was associated with high FOXP3⁺ cell infiltration (p = 0.001) and high BRCA2 expression (p < 0.0001). Survival analysis revealed that positive PD‐L1 (p = 0.046) and PD‐L2 (p = 0.028) expression on TCs was an independent risk factor for unfavourable disease‐specific survival (DSS). Furthermore, positive PD‐L2 expression on TCs was an independent risk factor for lower DSS in the pN0 (p = 0.023), moderate and well tumour differentiation (p = 0.004), low BRCA1 (p = 0.017), wild‐type p53 (p = 0.034), and proficient mismatch repair (p = 0.004) subgroups. Moreover, post‐operative adjuvant chemotherapy could significantly affect DSS, regardless of PD‐L1/PD‐L2 expression status (positive or negative) on TCs, while it only prolonged DSS in PDL1‐ICs⁽⁻⁾ (p < 0.0001) and PDL2‐ICs⁽⁻⁾ (p < 0.0001) subgroups. This study provides a comprehensive understanding of the roles of PD‐L1 and PD‐L2 in PDAC, supporting anti‐PD‐1 axis immunotherapy for PDAC.

SIGLEC15 amplifies immunosuppressive properties of tumor-associated macrophages in pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) usually presents infrequent infiltration of T lymphocytes. The known immune-checkpoint inhibitors to date focus on activating T cells and manifest limited effectiveness in PDAC. SIGLEC15 was identified as a novel tumor-associated macrophage (TAM)-related immune-checkpoint in other cancer types, while its immunosuppressive role and clinical significance remained unclear in PDAC. In our study, SIGLEC15 presented immunosuppressive relevance in PDAC via bioinformatic analysis and expressed on TAM and PDAC cells. SIGLEC15+ TAM, rather than SIGLEC15+ PDAC cells or SIGLEC15- TAM, correlated with poor prognosis and immunosuppressive microenvironment in the PDAC microarray cohort. Compared with SIGLEC15- TAM, SIGLEC15+ TAM presented an M2-like phenotype that could be modulated by SIGLEC15 in a tumor cell-dependent manner. In mechanism, SIGLEC15 interacted with PDAC-expressed sialic acid, preferentially α-2, 3 sialic acids, to stimulate SYK phosphorylation in TAM, which further promoted its immunoregulatory cytokines and chemokines production. In vivo, SIGLEC15+ TAM also presented an M2-like phenotype, accelerated tumor growth, and facilitated immunosuppressive microenvironment, which was greatly abolished by SYK inhibitor. Our study highlighted a novel M2-promoting function of SIGLEC15 and strongly suggested SIGLEC15 as a potential immunotherapeutic target for PDAC.

Tumoral and Stromal Pdl1 and Pdl2 Checkpoints Immunohistochemical Expression in Pancreatic Ductal Adenocarcinoma, a Promising Field Of Study

Background: Pancreatic ductal adenocarcinoma (PDAC) is world-widely considered as one of the most malignant tumors. Programmed cell death protein 1 (PD-1), via its ligands PDL1 and PDL2 plays a critical role in cancer immunoediting. The ligands are expressed in many solid tumors and there is an emerging hope of using anti-PDL in cancer immunotherapy.   Material and methods: This study included 40 patients with PDAC who underwent pancreaticoduodenectomy. PDL1 and PDL2 pancreatic expression were evaluated in these patients using immunohistochemical staining and correlated their expression levels with each patient’s reported clinicopathological features.   Results: There were significant relations between high tumoral PDL1 expression and the PDAC tumor histologic grade (p= 0.021) and the tumor status (T) (p= 0.022), while the stromal expression of PDL1 showed non-significant relation with any of the studied features. There were significant relations between high tumoral PDL2 expression and tumor stage (p=0.012), while the stromal expression of PDL2 showed significant relation with tumor status, lymph node status, tumor stage and the presence lympho-vascular invasion with P value equal 0.001, 0.009, 0.009, 0.045 respectively. Conclusion: This study showed that in PDAC patients high tumoral PDL1 and PDL2 expression was associated with some important prognostic factors, while only stromal PDL2 expression was significantly associated with most of the studied prognostic features emphasizing a role of both markers in the prognosis of this neoplasm.

Differential expression of PD‑L1 and PD‑L2 is associated with the tumor microenvironment of TILs and M2 TAMs and tumor differentiation in non‑small cell lung cancer

To improve the treatment strategy of immune-checkpoint inhibitors for non-small cell lung cancer (NSCLC), a comprehensive analysis of programmed death-ligand (PD-L)1 and PD-L2 expression is clinically important. The expression of PD-L1 and PD-L2 on both tumor cells (TCs) and tumor-infiltrating immune cells (ICs) was investigated, with respect to tumor-infiltrating lymphocytes (TILs) and M2 tumor-associated macrophages (TAMs), which are key components of the tumor microenvironment, in 175 patients with resected NSCLC. The TIL and M2 TAM densities were associated with the expression of PD-L1 on the two TCs (both P<0.0001) and ICs (both P<0.0001). The TIL and M2 TAM densities were also associated with the expression of PD-L2 on both TCs (P=0.0494 and P=0.0452, respectively) and ICs (P=0.0048 and P=0.0125, respectively). However, there was no correlation between the percentage of PD-L1-positive TCs and the percentage of PD-L2-positive TCs (r=0.019; P=0.8049). Meanwhile, tumor differentiation was significantly associated with the PD-L1 expression on TCs and ICs (P=0.0002 and P<0.0001, respectively). By contrast, tumor differentiation was inversely associated with the PD-L2 expression on both TCs and ICs (P=0.0260 and P=0.0326, respectively). In conclusion, the combined evaluation of PD-L1 and PD-L2 expression could be clinically important in the treatment strategy of immune-checkpoint inhibitors in patients with NSCLC. In particular, the evaluation of PD-L2 expression may be necessary for patients with PD-L1-negative NSCLC.

Insufficiency of compound immune checkpoint blockade to overcome engineered T cell exhaustion in pancreatic cancer

BACKGROUND

Achieving robust responses with adoptive cell therapy for the treatment of the highly lethal pancreatic ductal adenocarcinoma (PDA) has been elusive. We previously showed that T cells engineered to express a mesothelin-specific T cell receptor (TCRMsln) accumulate in autochthonous PDA, mediate therapeutic antitumor activity, but fail to eradicate tumors in part due to acquisition of a dysfunctional exhausted T cell state.

METHODS

Here, we investigated the role of immune checkpoints in mediating TCR engineered T cell dysfunction in a genetically engineered PDA mouse model. The fate of engineered T cells that were either deficient in PD-1, or transferred concurrent with antibodies blocking PD-L1 and/or additional immune checkpoints, were tracked to evaluate persistence, functionality, and antitumor activity at day 8 and day 28 post infusion. We performed RNAseq on engineered T cells isolated from tumors and compared differentially expressed genes to prototypical endogenous exhausted T cells.

RESULTS

PD-L1 pathway blockade and/or simultaneous blockade of multiple coinhibitory receptors during adoptive cell therapy was insufficient to prevent engineered T cell dysfunction in autochthonous PDA yet resulted in subclinical activity in the lung, without enhancing anti-tumor immunity. Gene expression analysis revealed that ex vivo TCR engineered T cells markedly differed from in vivo primed endogenous effector T cells which can respond to immune checkpoint inhibitors. Early after transfer, intratumoral TCR engineered T cells acquired a similar molecular program to prototypical exhausted T cells that arise during chronic viral infection, but the molecular programs later diverged. Intratumoral engineered T cells exhibited decreased effector and cell cycle genes and were refractory to TCR signaling.

CONCLUSIONS

Abrogation of PD-1 signaling is not sufficient to overcome TCR engineered T cell dysfunction in PDA. Our study suggests that contributions by both the differentiation pathways induced during the ex vivo T cell engineering process and intratumoral suppressive mechanisms render engineered T cells dysfunctional and resistant to rescue by blockade of immune checkpoints.

Prognostic Implications of Intratumoral and Peritumoral Infiltrating Lymphocytes in Pancreatic Ductal Adenocarcinoma

This study aimed to elucidate the prognostic implications of intratumoral and peritumoral infiltrating T-lymphocytes in pancreatic ductal adenocarcinoma (PDAC) through a meta-analysis. A total of 18 eligible studies and 2453 PDAC patients were included in the present study. Intratumoral and peritumoral infiltrating lymphocytes were evaluated using various markers, such as CD3, CD4, CD8, FOXP3, and immune cell score. The correlations between these parameters and overall and disease-free survival were investigated and used in the meta-analysis. High intratumoral infiltration of CD3-, CD4-, and CD8-expressing lymphocytes was significantly correlated with better overall survival (hazard ratio (HR) 0.747, 95% confidence interval (CI) 0.620-0.900, HR 0.755, 95% CI 0.632-0.902, and HR 0.754, 95% CI 0.611-0.930, respectively). However, there was no significant correlation between PDAC prognosis and intratumoral FOXP3 or immune cell score (HR 1.358, 95% CI 1.115-1.655 and HR 0.776, 95% CI 0.566-1.065, respectively). Moreover, there was no significant correlation between the prognosis and peritumoral infiltrating T-lymphocytes. In evaluations of disease-free survival, only high intratumoral CD4 infiltration was correlated with a better prognosis (HR 0.525, 95% CI 0.341-0.810). Our results showed that high intratumoral infiltrating lymphocytes were significantly correlated with a better PDAC prognosis. However, among the tumor-infiltrating lymphocytes, CD3, CD4, and CD8 had prognostic implications, but not FOXP3 and immune cell score.

Clinical and Prognostic Value of Antigen-Presenting Cells with PD-L1/PD-L2 Expression in Ovarian Cancer Patients

The latest literature demonstrates the predominant role of the programmed cell death axis (PD-1/PD-L1/PD-L2) in ovarian cancer (OC) pathogenesis. However, data concerning this issue is ambiguous. Our research aimed to evaluate the clinical importance of PD-L1/PD-L2 expression in OC environments. We evaluated the role of PD-L1/PD-L2 in OC patients (n = 53). The analysis was performed via flow cytometry on myeloid (mDCs) and plasmacytoid dendritic cells (pDCs) and monocytes/macrophages (MO/MA) in peripheral blood, peritoneal fluid (PF), and tumor tissue (TT). The data were correlated with clinicopathological characteristics and prognosis of OC patients. The concentration of soluble PD-L1 (sPD-L1) and PD-1 in the plasma and PF were determined by ELISA. We established an accumulation of PD-L1+/PD-L2+ mDCs, pDCs, and MA in the tumor microenvironment. We showed an elevated level of sPD-L1 in the PF of OC patients in comparison to plasma and healthy subjects. sPD-L1 levels in PF showed a positive relationship with Ca125 concentration. Moreover, we established an association between higher sPD-L1 levels in PF and shorter survival of OC patients. An accumulation of PD-L1+/PD-L2+ mDCs, pDCs, and MA in the TT and high sPD-L1 levels in PF could represent the hallmark of immune regulation in OC patients.

PD-L2 based immune signature confers poor prognosis in HNSCC

PD-L2 expression is an important predictor of anti-PD-1 therapy efficacy in patients with head and neck squamous cell carcinoma (HNSCC). However, whether the PD-L2-based immune signature can serve as a prognostic biomarker for patients with HNSCC remains unclear. Here, we reported that PD-L2 was positively stained in 62.7% of tumors, which was more than twice as that of PD-L1, and in 61.4% of patients with PD-L1-negative tumors. Survival tree analysis (STA) revealed that PD-L2^high was an independent predictor of poor overall survival (OS). Six patterns were generated from STA, demonstrating that patients with PD-L2^lowCD3^high were associated with an improved median OS of 72 months and prognostic index (PI) of -3.95 (95% CI, -5.14 to -2.76), whereas patients with PD-L2^highCD3^lowCD8^low to a median OS of 10 months and PI of 1.43 (95% CI, 0.56 to 2.30). Analysis of single-cell RNA sequencing showed that PD-L2 expression was associated with IL-6 expression. We confirmed that IL-6 augments PD-L2 expression in HNSCC cell lines. The PD-L2-based immune signature can serve as an effective biomarker for anti-PD-1 therapy. In addition, PD-L2 may serve as a potential immunotherapeutic target, and we propose anti-IL6 therapy in the adjuvant setting for patients with HNSCC with high PD-L2 expression.

Prognostic relevance of programmed cell death 1 ligand 2 (PDCD1LG2/PD-L2) in patients with advanced stage colon carcinoma treated with chemotherapy

Colorectal cancer (CRC) is the leading cause of cancer-related mortality worldwide. Although the role of tumor programmed cell death 1 ligand 1 (PD-L1) in suppressing antitumor immunity has been validated in various malignances, the impact of PD-L2 (PD-L2/PDCD1LG2) within tumors remains elusive. Here, we examined tumor PD-L2 expression by immunohistochemical analysis and assessed its association with clinicopathological characteristics and the infiltration of intratumoral T lymphocytes in colon carcinoma patients (n = 1264). We found that tumor PD-L2 status was correlated with perineural invasion (PNI) and associated with survival outcome in colon carcinoma patients. The level of tumor PD-L2 was positively associated with tumor PD-L1 expression but inversely associated with the density of CD8⁺ tumor-infiltrating lymphocytes (TILs). Patients with elevated tumor PD-L2 levels had a favorable 5-year overall survival (OS) compared to patients with low PD-L2 levels (57% vs 40%, p < 0.001), especially in advanced stage colon carcinoma patients. Low tumor PD-L2 expression was associated with an increased 5-year OS risk among advanced stage colon carcinoma patients by univariate analysis [hazard ratio (HR) = 1.69, 95% CI 1.324–2.161, p < 0.001] and multivariate analysis [HR = 1.594, 95% CI 1.206–2.106, p = 0.001]. Moreover, tumor PD-L2 expression was inversely associated with the lymphocytic reaction in advanced stage colon carcinoma, suggesting that PD-L2 may be upregulated by a compensatory mechanism to inhibit T cell-mediated anticancer immunity. Taken together, these results show that tumor PD-L2 expression may be an independent prognostic factor for survival outcome in patients with advanced stage colon carcinoma.

Prognostic and clinicopathological utility of PD-L2 expression in patients with digestive system cancers: A meta-analysis

OBJECTIVE

Programmed death ligand-2 (PD-L2)has been detected in various cancers. However, its prognostic value in digestive system cancers (DSCs) remains unclear. Accordingly, this meta-analysis investigated the prognostic and clinicopathological utility of PD-L2 in patients with DSCs.

METHODS

We systematically searched PubMed, EMBASE, Web of Science, ClinicalTrials.gov., Scopus, and Cochrane Library databases for eligible studies up to April 30, 2020. The hazard ratio (HR), odds ratio (OR), and corresponding 95% confidence interval (CI) of the outcomes were calculated.

RESULTS

Twenty two studies with 4886 patients were included in this meta-analysis. The pooled results showed that PD-L2 overexpression was significantly associated with poor overall survival (OS) (HR 1.470, 95% CI: 1.252-1.728, p < 0.001) and worse disease-free survival (DFS) (HR1.598, 95% CI: 1.398-1.826, p < 0.001). Subgroup analysis revealed that elevated PD-L2 was a significant prognostic indicator of worse OS in hepatocellular carcinoma (HR 1.703, 95% CI: 1.456-1.991, p < 0.001) and colorectal cancer (HR 3.811, 95% CI: 1.718-8.454, p = 0.001). Concerning clinicopathologic factors, PD-L2 overexpression was associated with lymphatic metastasis (OR 1.394., 95% CI: 1.101-1.764, p = 0.006), tumor metastasis (OR 1.599, 95% CI: 1.072-2.383, p = 0.021), and the histopathological stage (OR 0.704, 95% CI: 0.566-0.875, p = 0.002).

CONCLUSION

PD-L2 overexpression in DSCs after surgery might predict a poor prognosis, especially in hepatocellular carcinoma and colorectal cancer. Larger patient cohorts are needed to validate its prognostic role.

Oncogenic function of TRIM2 in pancreatic cancer by activating ROS-related NRF2/ITGB7/FAK axis

Evidence suggests that tripartite motif-containing 2 (TRIM2) is associated with carcinogenic effects in several malignancies. However, the expression patterns and roles of TRIM2 in pancreatic cancer are rarely studied. Our study demonstrated that TRIM2 was expressed in a high percentage of pancreatic tumors. High TRIM2 expression was negatively correlated with the outcome of pancreatic cancer. TRIM2 silencing significantly inhibited the proliferation, migration, invasion, and in vivo tumorigenicity of pancreatic cancer cells. Regarding the mechanism involved, TRIM2 activated ROS-related E2-related factor 2 (NRF2)/antioxidant response element (ARE) signaling and the integrin/focal adhesion kinase (FAK) pathway. Treatment of pancreatic cancer cells with the antioxidant N-acetyl-L-cysteine decreased ROS activity and expression level of NRF2 and ITGB7. Increased translocation of NRF2 protein into nucleus further rescued the inhibited ITGB7 transcription. Moreover, NRF2 bound to the potential ARE on the promoter region and enhanced the transcriptional activity of ITGB7, indicating the bridging effect of NRF2 between the two signaling pathways. In summary, our study provides evidence that upregulated TRIM2 in pancreatic cancer predicts short survival for pancreatic cancer patients. TRIM2 accelerates pancreatic cancer progression via the ROS-related NRF2/ITGB7/FAK axis.

Understanding the Role of Innate Immune Cells and Identifying Genes in Breast Cancer Microenvironment

The innate immune system is the first line of defense against invading pathogens and has a major role in clearing transformed cells, besides its essential role in activating the adaptive immune system. Macrophages, dendritic cells, NK cells, and granulocytes are part of the innate immune system that accumulate in the tumor microenvironment such as breast cancer. These cells induce inflammation in situ by secreting cytokines and chemokines that promote tumor growth and progression, in addition to orchestrating the activities of other immune cells. In breast cancer microenvironment, innate immune cells are skewed towards immunosuppression that may lead to tumor evasion. However, the mechanisms by which immune cells could interact with breast cancer cells are complex and not fully understood. Therefore, the importance of the mammary tumor microenvironment in the development, growth, and progression of cancer is widely recognized. With the advances of using bioinformatics and analyzing data from gene banks, several genes involved in NK cells of breast cancer individuals have been identified. In this review, we discuss the activities of certain genes involved in the cross-talk among NK cells and breast cancer. Consequently, altering tumor immune microenvironment can make breast tumors more responsive to immunotherapy.

Programmed death-ligand 2 (PD-L2) expression in bladder cancer

OBJECTIVE

Immune checkpoint blockade is an optional and effective therapy for bladder cancer. The present study was aimed to investigate the expression of programmed death ligand-2 (PD-L2) in patients with bladder cancer.

MATERIALS AND METHODS

Paraffin-embedded tissues of 92 patients with bladder cancer were obtained. Then immunohistochemistry of PD-L2 was performed. The expression intensity of PD-L2 was defined with score 0, 1, 2 and 3, in compliance with negative, weak, moderate, and strong, respectively. The association of PD-L2 expression with clinical characteristics was analyzed. A P < 0.05 was considered as significantly different.

RESULTS

By defining the expression intensity of PD-L2 with score 0 to 3, 73.9% of patients (68/92) had a positive expression of PD-L2, and 43.5% (40/92) had a mediate or strong expression. Furthermore, high expression PD-L2 (mediate or strong expression) was more common among patients ≤ 70 y (P = 0.038) and those with smoke history (P = 0.045). The univariate Kaplan-Meier analysis indicated that high expression of PD-L2 was associated with both shorter overall survival (OS) (78.3 vs. 60.3 months; P = 0.037) and shorter disease-free survival (44.3 vs. 22.5 months; P = 0.004). The multivariate COX regression model showed that high expression of PD-L2 was a poor factor of disease-free survival (hazard ratio = 0.537, 95%CI 0.322-0.898; P = 0.018), but not OS (hazard ratio = 0.565, 95%CI 0.253-1.262; P = 0.164).

CONCLUSION

Bladder cancer had a high expression of PD-L2. And high expression of PD-L2 may indicate worse prognosis. It may be a potential immunotherapeutic target of immune checkpoint blockade for bladder cancer.

The reciprocal regulation between host tissue and immune cells in pancreatic ductal adenocarcinoma: new insights and therapeutic implications

Pancreatic ductal adenocarcinoma (PDAC) is the fourth leading cause of cancer-related death and is one of the most difficult-to-treat cancers. Surgical resection and adjuvant therapy have limited effects on the overall survival of PDAC patients. PDAC exhibits an immunosuppressive microenvironment, the immune response predicts survival, and activation of immune system has the potential to produce an efficacious PDAC therapy. However, chimeric antigen receptor T (CAR-T) cell immunotherapy and immune checkpoint blockade (ICB), which have produced unprecedented clinical benefits in a variety of different cancers, produce promising results in only some highly selected patients with PDAC. This lack of efficacy may be because existing immunotherapies mainly target the interactions between cancer cells and immune cells. However, PDAC is characterized by an abundant tumor stroma that includes a heterogeneous mixture of immune cells, fibroblasts, endothelial cells, neurons and some molecular events. Immune cells engage in extensive and dynamic crosstalk with stromal components in the tumor tissue in addition to tumor cells, which subsequently impacts tumor suppression or promotion to a large extent. Therefore, exploration of the interactions between the stroma and immune cells may offer new therapeutic opportunities for PDAC. In this review, we discuss how infiltrating immune cells influence PDAC development and explore the contributions of complex components to the immune landscape of tumor tissue. The roles of stromal constituents in immune modulation are emphasized. We also predict potential therapeutic strategies to target signals in the immune network in the abundant stromal microenvironment of PDAC.

Classical Hodgkin's Lymphoma in the Era of Immune Checkpoint Inhibition

The ligation of programmed cell death 1 (PD-1) with programmed cell death ligand PD-L activates the immune checkpoint leading to T-cell dysfunction, exhaustion, and tolerance, especially in Hodgkin lymphoma (HL) where the PD-L/ Janus kinase (Jak) signaling was frequently found altered. Anti-PD-1 or anti-PD-L1 monoclonal antibodies can reverse this immune checkpoint, releasing the brake on T-cell responses. The characterization of the mechanisms regulating both the expression of PD-1 and PD-L and their function(s) in HL is ongoing. We provide in this review the recent findings focused on this aim with special attention on the major research topics, such as adverse events and resistance to PD-1–PD-L1 inhibitor treatment, together with a part about angiogenesis, extracellular vesicles, and microbiome in HL pathogenesis.