Correlation of Systemic Inflammation Parameters and Serum SLFN11 in Small Cell Lung Cancer-A Prospective Pilot Study.

BACKGROUND AND OBJECTIVES: The objective of this research was to analyze the correlation of the neutrophil-to-lymphocyte ratio (NLR), C-reactive protein (CRP), soluble programmed cell death ligand 1 (sPD-L1), and Schlafen 11 (SLFN11) with the response to first-line chemotherapy in a cohort of small cell lung cancer (SCLC) patients, and to determine their potential as predictive serum biomarkers. MATERIALS AND METHODS: A total of 60 SCLC patients were included. Blood samples were taken to determine CRP, sPD-L1, and SLFN11 levels. The first sampling was performed before the start of chemotherapy, the second after two cycles, and the third after four cycles of chemotherapy. RESULTS: The patients who died earlier during the study had NLR and SLFN11 concentrations significantly higher compared to the survivor group. In the group of survivors, after two cycles of chemotherapy, the NLR ratio decreased significantly (p < 0.01), but after four cycles, the NLR ratio increased (p < 0.05). Their serum SLFN11 concentration increased significantly (p < 0.001) after two cycles of chemotherapy, but after four cycles, the level of SLFN11 fell significantly (p < 0.01). CRP, NLR, and SLFN11 were significant predictors of patient survival according to Kaplan-Meier analysis. The combination of inflammatory parameters and SLFN11 with a cutoff value above the 75th percentile of the predicted probability was associated with significantly lower overall survival in SCLC patients (average survival of 3.6 months vs. 4.8 months). CONCLUSION: The combination of inflammatory markers and the levels of two specific proteins (sPD-L1, SLFN11) could potentially serve as a non-invasive biomarker for predicting responses to DNA-damaging therapeutic agents in SCLC.

Soluble programmed death ligand 1 as prognostic biomarker in non-small cell lung cancer patients receiving nivolumab, pembrolizumab or atezolizumab therapy.

Many studies have focused on the prognostic role of soluble programmed death ligand 1 (sPD-L1) in non-small cell lung cancer (NSCLC), but outcomes are ambiguous and further investigations are needed. We addressed the matter by studying sPD-L1 in baseline samples and in longitudinal samples taken prior to three subsequent cycles of anti-PD-1/anti-PD-L1 treatments. Eighty patients with NSCLC were enrolled. Median sPD-L1 level at baseline was 52 pg/mL [95% confidence interval (CI) 49-57]. In patients treated with pembrolizumab and nivolumab, the concentration of sPD-L1 remained rather stable throughout treatment. In contrast, sPD-L1 rose by 50-fold following the first cycle of atezolizumab therapy. We found the baseline level of sPD-L1 to be related to overall survival (OS) after two years of follow-up in simple Cox analysis (p = 0.006) and multiple Cox Regression, hazard ratio 1.02 (95% CI 1.00-1.03) (p = 0.033). There was no association between sPD-L1 and tissue PD-L1 expression, overall response rate, or progression free survival. In conclusion, sPD-L1 measured in baseline serum samples may be associated with OS in NSCLC patients receiving anti-PD1/anti-PD-L1 treatment. Importantly, the results signify that further research is warranted to explore the clinical utility of sPD-L1 in patients treated with anti-PD-L1.

Cytokine and soluble programmed death-ligand 1 levels in serum and plasma of cancer patients treated with immunotherapy: Preanalytical and analytical considerations.

AIM: To evaluate cytokine and soluble programmed death ligand-1 (sPD-L1) levels in the serum and plasma of cancer patients treated with immunotherapy, and to test different assays. METHODS: Three Luminex xMAP assays and two ELLA microfluidic cartridges were used to screen 28 immune-related biomarkers in 38 paired serum and citrate-theophylline-adenosine-dipyridamole (CTAD) plasma samples collected from 10 advanced melanoma or non-small cell lung cancer (NSCLC) patients at different time points during immunotherapy. RESULTS: Twenty-three of 28 biomarkers were detected both in serum and plasma by at least one of the assays, including IL-1ß, IL-2, IL-4, IL-5, IL-6, IL-8, IL-10, IL-12p70, GM-CSF, IFN-γ, TNF-α, VEGF, IP-10, MCP-1, eotaxin, fractalkine, G-CSF, IFN-α, IL-1RA, IL-13, IL-17A, MIP-1ß and sPD-L1. Conversely, FGF-2 and IL-1α were not detected in both matrices; GRO-α factor and EGF were detected only in serum and MIP-1α only in plasma. sPD-L1, MCP-1, IFN-γ, IL-8, MIP-1ß and VEGF were, respectively, 1.15-, 1.44-, 1.83-, 2.43-, 2.82-, 6.72-fold higher in serum, whereas IL-10, IL-4, IL-2 and IL-5 were 1.05-, 1.19-, 1.92- and 2.17-fold higher, respectively, in plasma. IP-10 levels were higher in plasma but, as well as for VEGF, the bias serum versus plasma varied depending on the assay used (IP-10: -5.7% to -145%; VEGF: 115% to 165%). No significant differences were found for the remaining nine analyzed cytokines. CONCLUSION: The cytokine and sPD-L1 levels may differ between serum and plasma samples collected from cancer patients treated with immunotherapy, and the results obtained can be influenced by the different characteristics of the tested assays. The standardization of pre-analytical and analytical procedures is therefore needed for the future implementation of these circulating biomarkers in clinical practice.

sPD-L1 and sPD-L2 in plasma of patients with lung cancer and their clinical significance.

INTRODUCTION: Lung cancer is the leading cause of cancer death worldwide. We aim here to determine the soluble programmed death ligand-1 (sPD-L1) and soluble programmed death ligand-2 (sPD-L2) levels in the plasma of patients with lung cancer and evaluate the clinical significance. METHODS: Plasma samples from 95 lung cancer patients and 55 healthy donors were collected, and the sPD-L1 and sPD-L2 levels were measured using the enzyme-linked immunosorbent assay. The correlations of the plasma sPD-L1 and sPD-L2 levels with clinicopathological status and survival of the patients were analyzed. RESULTS: The sPD-L1 and sPD-L2 levels in plasma of lung cancer patients were 713.8 (240.6-3815) pg/ mL and 3233(1122-13955) pg/ mL, respectively, which were significantly higher than those of the health donors 618.6 (189.1-1149) pg/ mL and 2182 (1133-3471) pg/ mL, and the plasma levels of sPD-L1 are correlated with sPD-L2. ROC results showed that both sPD-L1 and sPD-L2 were potential biomarker for lung cancer, and with a higher accuracy level when combined with CEA. Patients with Higher plasma sPD-L1 level (>713.75 pg/ mL) are associated with poor overall survival in advanced lung cancer patients (197 days vs 643 days). CONCLUSIONS: The combination of sPD-L1 and sPD-L2 could be used as adjunctive diagnostic, High level of plasma sPD-L1 rather than sPD-L2 is associated with poor prognosis in lung cancer patients.

Soluble PD-L1 reprograms blood monocytes to prevent cerebral edema and facilitate recovery after ischemic stroke.

Acute cerebral ischemia triggers a profound inflammatory response. While macrophages polarized to an M2-like phenotype clear debris and facilitate tissue repair, aberrant or prolonged macrophage activation is counterproductive to recovery. The inhibitory immune checkpoint Programmed Cell Death Protein 1 (PD-1) is upregulated on macrophage precursors (monocytes) in the blood after acute cerebrovascular injury. To investigate the therapeutic potential of PD-1 activation, we immunophenotyped circulating monocytes from patients and found that PD-1 expression was upregulated in the acute period after stroke. Murine studies using a temporary middle cerebral artery (MCA) occlusion (MCAO) model showed that intraperitoneal administration of soluble Programmed Death Ligand-1 (sPD-L1) significantly decreased brain edema and improved overall survival. Mice receiving sPD-L1 also had higher performance scores short-term, and more closely resembled sham animals on assessments of long-term functional recovery. These clinical and radiographic benefits were abrogated in global and myeloid-specific PD-1 knockout animals, confirming PD-1+ monocytes as the therapeutic target of sPD-L1. Single-cell RNA sequencing revealed that treatment skewed monocyte maturation to a non-classical Ly6Clo, CD43hi, PD-L1+ phenotype. These data support peripheral activation of PD-1 on inflammatory monocytes as a therapeutic strategy to treat neuroinflammation after acute ischemic stroke.

Different Prognostic Role of Soluble PD-L1 in the Course of Severe and Non-Severe COVID-19.

Understanding the link between COVID-19 and patient immune characteristics is crucial. We previously demonstrated that high levels of the soluble Programmed Death-Ligand1 (sPD-L1) at the beginning of the infection correlated with low lymphocyte number and high C-reactive protein (CRP), longer length of stay (LOS), and death. This study investigated whether sPD-L1 can be a prognosis biomarker during COVID-19. Severe and non-severe COVID-19 patients were enrolled at the University Hospital of Salerno. During hospitalization, at admission, and after 12-14 days, patients' data were collected, and sPD-L1 levels were measured by enzyme-linked immunosorbent assay. The peripheral lymphocyte number negatively correlated with the time of negativization (p = 0.006), length of stay (LOS) (p = 0.032), and CRP (p = 0.004), while sPD-L1 positively correlated with LOS (p = 0.015). Patients with increased sPD-L1 and lymphocyte number showed a shorter LOS than those with decreased sPD-L1 and lymphocyte number (p = 0.038) and those with increased sPD-L1 and decreased lymphocyte number (p = 0.025). Moreover, patients with increased sPD-L1 and decreased CRP had a shorter LOS than those with increased sPD-L1 and CRP (p = 0.034) and those with decreased sPD-L1 and CRP (p = 0.048). In conclusion, while at an early phase of COVID-19, sPD-L1 promotes an immune escape, later, it might act to dampen an excessive immune response, proving its role in COVID-19 prognosis.

Soluble Programmed Death-Ligand 1 (sPD-L1) as a Promising Marker for Head and Neck Squamous Cell Carcinoma: Correlations With Clinical and Demographic Characteristics.

Background and objective Head and neck squamous cell carcinoma (HNSCC) is a prevalent cancer type that affects the mucosal lining of the upper aerodigestive tract. Soluble programmed death-ligand 1 (sPD-L1) is a significant factor in hindering T cells' function, which prevents cancer cells from being detected by the immune system. This means that sPD-L1 is an essential component in the immune evasion of cancer. This study aimed to explore the potential of sPD-L1 as a prognostic biomarker for patients with HNSCC undergoing concurrent chemotherapy and radiation therapy. Methodology The study included 106 patients with locally advanced HNSCC who received three courses of induction chemotherapy followed by concurrent chemoradiation and 60 healthy subjects as controls. sPD-L1 levels were measured using an enzyme-linked immunosorbent assay (ELISA) kit, and the cutoff value was determined based on receiver operating characteristic (ROC) curve analysis. Results The results showed that sPD-L1 levels were significantly higher in HNSCC patients compared to healthy controls, with a cutoff value of 31.51 pg/mL. Higher sPD-L1 levels were associated with poorer overall survival rates. Conclusions These findings suggest that sPD-L1 may serve as a valuable prognostic biomarker for HNSCC patients undergoing concurrent chemotherapy and radiation therapy. The study highlights the importance of exploring new biomarkers and therapeutic strategies for HNSCC to improve patient outcomes and reduce morbidity and mortality rates associated with this disease.

Decreased serum soluble programmed cell death ligand-1 level as a potential biomarker for missed miscarriage.

STUDY QUESTION: Can maternal serum levels of soluble programmed cell death-1 (sPD-1) and its ligand (sPD-L1) serve as biomarkers for missed miscarriage (MM)? SUMMARY ANSWER: Serum sPD-L1 levels are significantly decreased in MM patients and may serve as a potential predictive biomarker for miscarriage. WHAT IS KNOWN ALREADY: Programmed cell death-1 (PD-1) and its ligand (PD-L1) comprise important immune inhibitory checkpoint signaling to maintain pregnancy. Their soluble forms are detectable in human circulation and are associated with immunosuppression. STUDY DESIGN, SIZE, DURATION: Three independent cohorts attending tertiary referral hospitals were studied. The first (discovery) cohort was cross-sectional and included MM patients and healthy pregnant (HP) women matched on BMI. The second validation cohort contained MM patients and women with legally induced abortion (IA). The third prospective observational study recruited subjects requiring IVF treatment. PARTICIPANTS/MATERIALS, SETTING, METHODS: In the discovery cohort, we enrolled 108 MM patients and 115 HP women who had a full-term pregnancy at 6-14 weeks of gestation. In the validation cohort, we recruited 25 MM patients and 25 women with IA. Blood samples were collected at the first prenatal visit for HP women or on the day of dilatation and curettage surgery (D&C) for MM and IA subjects to determine serum sPD-1 and sPD-L1 levels. Placenta samples were harvested during the D&C within the validation cohort to measure gene and protein expression. The prospective cohort collected serial blood samples weekly from 75 volunteers with embryo transfer (ET) after IVF. MAIN RESULTS AND THE ROLE OF CHANCE: Circulating sPD-L1 levels were reduced by 50% in patients with MM (55.7 ± 16.04 pg/ml) compared to HP controls (106.7 ± 58.46 pg/ml, P < 0.001) and the difference remained significant after adjusting for maternal age and gestational age, whereas no significant differences in sPD-1 level were observed. Likewise, serum sPD-L1 was lower in MM patients than in IA subjects and accompanied by downregulated PD-L1-related gene expression levels in the placenta. In the IVF cohort, applying the changing rate of sPD-L1 level after ET achieved a predictive performance for miscarriage with receiver operating characteristics = 0.73 (95% CI: 0.57-0.88, P < 0.01). LIMITATIONS, REASONS FOR CAUTION: The study was mainly confined to East Asian pregnant women. Further large prospective pregnancy cohorts are required to validate the predictive performance of sPD-L1 on miscarriage. WIDER IMPLICATIONS OF THE FINDINGS: Reduced circulating sPD-L1 level and downregulated placental PD-L1 expression in miscarriage indicate that dysfunction in PD-L1 signals is a potential underlying mechanism for pregnancy loss. Our findings further extend the importance of the PD-L1 axis in pregnancy maintenance in early pregnancy. STUDY FUNDING/COMPETING INTEREST(S): This study was financially supported by grants from the Subject Innovation Team of Shaanxi University of Chinese Medicine (2019-Y502), General Research Fund (14122021), and Key Laboratory of Model Animal Phenotyping and Basic Research in Metabolic Diseases (2018KSYS003). The authors declare that they have no competing interests to be disclosed. TRIAL REGISTRATION NUMBER: N/A.

Thymoquinone, a Novel Multi-Strike Inhibitor of Pro-Tumorigenic Breast Cancer (BC) Markers: CALR, NLRP3 Pathway and sPD-L1 in PBMCs of HR+ and TNBC Patients.

Breast cancer (BC) is not only a mass of malignant cells but also a systemic inflammatory disease. BC pro-tumorigenic inflammation has been shown to promote immune evasion and provoke BC progression. The NOD-like receptor (NLR) family pyrin domain-containing protein 3 (NLRP3) inflammasome is activated when pattern recognition receptors (PRRs) sense danger signals such as calreticulin (CALR) from damaged/dying cells, leading to the secretion of interleukin-1ß (IL-1ß). CALR is a novel BC biological marker, and its high levels are associated with advanced tumors. NLRP3 expression is strongly correlated with an elevated proliferative index Ki67, BC progression, metastasis, and recurrence in patients with hormone receptor-positive (HR+) and triple-negative BC (TNBC). Tumor-associated macrophages (TAMs) secrete high levels of IL-1ß promoting endocrine resistance in HR+ BC. Recently, an immunosuppressive soluble form of programmed death ligand 1 (sPD-L1) has been identified as a novel prognostic biomarker in triple-negative breast cancer (TNBC) patients. Interestingly, IL-1ß induces sPD-L1 release. BC Patients with elevated IL-1ß and sPD-L1 levels show significantly short progression-free survival. For the first time, this study aims to investigate the inhibitory impact of thymoquinone (TQ) on CALR, the NLRP3 pathway and sPD-L1 in HR+ and TNBC. Blood samples were collected from 45 patients with BC. The effect of differing TQ concentrations for different durations on the expression of CALR, NLRP3 complex components and IL-1ß as well as the protein levels of sPD-L1 and IL-1ß were investigated in the peripheral blood mononuclear cells (PBMCs) and TAMs of TNBC and HR+ BC patients, respectively. The findings showed that TQ significantly downregulated the expression of CALR, NLRP3 components and IL-1ß together with the protein levels of secreted IL-1ß and sPD-L1. The current findings demonstrated novel immunomodulatory effects of TQ, highlighting its potential role not only as an excellent adjuvant but also as a possible immunotherapeutic agent in HR+ and TNBC patients.

Serum sPD-L1 levels are elevated in patients with viral diseases, bacterial sepsis or in patients with impaired renal function compared to healthy blood donors.

OBJECTIVES: Immune checkpoints play an important role in maintaining the balance of the immune system and in the development of autoimmune diseases. A central checkpoint molecule is the programmed cell death protein 1 (PD-1, CD279) which is typically located on the surface of T cells. Its primary ligand PD-L1 is expressed on antigen presenting cells and on cancer cells. Several variants of PD-L1 exist, among these soluble molecules (sPD-L1) present in serum at low concentrations. sPD-L1 was found elevated in cancer and several other diseases. sPD-L1 in infectious diseases has received relatively little attention so far and is therefore subject of this study. METHODS: sPD-L1 serum levels were determined in 170 patients with viral infections (influenza, varicella, measles, Dengue fever, SARS-CoV2) or bacterial sepsis by ELISA and compared to the levels obtained in 11 healthy controls. RESULTS: Patients with viral infections and bacterial sepsis generally show significantly higher sPD-L1 serum levels compared to healthy donors, except for varicella samples where results do not reach significance. sPD-L1 is increased in patients with impaired renal function compared to those with normal renal function, and sPD-L1 correlates significantly with serum creatinine. Among sepsis patients with normal renal function, sPD-L1 serum levels are significantly higher in Gram-negative sepsis compared to Gram-positive sepsis. In addition, in sepsis patients with impaired renal function, sPD-L1 correlates positively with ferritin and negatively with transferrin. CONCLUSIONS: sPD-L1 serum levels are significantly elevated in patients with sepsis, influenza, mesasles, Dengue fever or SARS-CoV2. Highest levels are detectable in patients with measles and Dengue fever. Also impaired renal function causes an increase in levels of sPD-L1. As a consequence, renal function has to be taken into account in the interpretation of sPD-L1 levels in patients.

Prognostic value of soluble programmed cell death ligand-1 (sPD-L1) in lymphoma: a systematic review and meta-analysis.

Previous studies on the prognostic value of soluble programmed cell death ligand 1 (sPD-L1) in lymphoma patients have yielded inconsistent results. Here, we conducted a meta-analysis and systematic review to investigate the prognostic significance of sPD-L1 in lymphoma, especially in diffuse large B-cell lymphoma (DLBCL) and NK/T-cell lymphoma (NK/TCL). A total of 11 studies with 1185 patients were included in the meta-analysis, and the combined results indicated that high sPD-L1 levels were associated with worse overall survival (OS) (HR = 2.27, 95%CI: 1.70-3.04) and progression-free survival (PFS) (HR = 2.68, 95%CI: 1.92-3.75). Furthermore, subgroup analysis showed that sPD-L1 remained a significant prognostic factor for OS. The meta-analysis indicated that sPD-L1 may be a potential prognostic biomarker for lymphoma, especially in DLBCL and NK/TCL, and high sPD-L1 levels were associated with worse survival prognosis.

Prognostic and predictive role of soluble programmed death ligand-1 in head and neck cancer

Abstract Objectives The aim of the study was to investigate clinical significance of soluble PD-L1 (sPD-L1) serum level in head and neck cancer and to evaluate its role as a possible prognostic and predictive biomarker. Methods A prospective analysis of sPD-L1 levels in 60 patients diagnosed and treated due to malignant and non-malignant lesions in the region of head and neck was performed in peripheral blood by an ELISA test. Results The range of sPD-L1 in the study group was 0.16-1.63 ng/mL, mean 0.64 ± 0.32. There were no differences in the mean sPD-L1 regarding patients' age, sex, and the localization of the lesion. Statistically significant difference was revealed in the average sPD-L1 level (p = 0.006) depending on the histopathological advancement of the lesions, 0.704 ± 0.349 and 0.512 ± 0.177 respectively in the malignant and benign group. The separate analysis of laryngeal lesions confirmed statistical difference in sPD-L1 (p = 0.002) for the malignant lesions (0.741 ± 0.353) compared with the benign (0.489 ± 0.175). The sPD-L1 level of 0.765 ng/mL or higher, revealed 35% sensitivity and 95.5% specificity for the diagnosis of head and neck malignant lesions (AUC = 0.664, 95% CI 0.529‒0.8, p-value = 0.039). The 1-year DFS was 83.3% in the group of patients with low sPD-L1 levels (< 0.765 ng/mL) and 53.8% in patients with high sPD-L1 (≥0.765 ng/mL). The 2-year OS were 68% and 69.2% respectively in both groups. The log-rank test confirmed statistically significant prognostic value of sPD-L1 level for 1-year DFS (p-value = 0.035). Conclusions sPD-L1 is a promising prognostic and early recurrence predictive biomarker for head and neck cancers, most significantly for laryngeal lesions. Level of evidence 3.

Meta-analysis of the prognostic value of soluble programmed death ligand-1 (sPD-L1) in cancers.

BACKGROUND: The soluble programmed death ligand-1 (sPD-L1) and its prognostic role in cancers have been investigated in numerous studies. However, due to the inconsistency on some findings, this meta-analysis was performed to assess the prognostic value of sPD-L1 in patients with cancer. METHODS: We searched the PubMed, Web of Science, MEDLINE, Wiley Online Library and ScienceDirect, and screened the studies for eligibility. Recurrence-free survival (RFS), progression-free survival (PFS) and disease-free survival (DFS) were for short term survival. The overall survival (OS) was for long term survival. RESULTS: Forty studies with 4441 patients were included in this meta-analysis. Elevated sPD-L1 was associated with short OS [HR = 2.44 (2.03-2.94), p = 0.000]. Moreover, a high sPD-L1 was predictive of worse DFS/RFS/PFS [HR = 2.52 (1.83-3.44), p = 0.000]. In addition, high sPD-L1 was consistently correlated with poor OS in irrespective of study type, univariate and multivariate analysis, ethnicity, cut-off value of sPD-L1, sample and treatment. In the subgroup analysis, high sPD-L1 was correlated with poor OS in gastrointestinal cancer, lung cancer, hepatic cancer, oesophageal cancer and clear cell renal cell carcinoma. CONCLUSIONS: The present meta-analysis showed that a high level of sPD-L1 was associated with worse prognosis in some types of cancer.

Soluble forms of PD-1 and sPD-L1/2 in serum and urine of patients with head and neck cancer and their clinical significance.

This study explored the soluble forms of PD-1 and sPD-L1/2 in serum and urine of patients with head and neck cancer (HNCs) and associated the data with clinical state and 5-year survival. The sPD-1 and sPD-L1/2 levels were evaluated by ELISA in sufferers (N=110) and normal controls (N=82). Patients in the case group were more likely to be male smokers or former smokers. Compared with the normal control group, the serum levels of sPD-1, sPD-L1 and sPD-L2 and the urine level of sPD-L1 in patients with HNCs were increased. Furthermore, sPD-1 and sPD-L1 serum levels existed a positive connection, and sPD-1 and sPD-L2 serum levels positively correlated in HNCs sufferers. The urine sPD-1 and sPD-L1 had a positive relationship. sPD-1 serum levels had a positive connection with urine sPD-1, sPD-L1 urine levels had a positive relationship with sPD-L1, and sPD-L2 serum levels positively connected to urine sPD-L2. Lower serum sPD-1 and sPD-L1/L2 were associated with disease progression and survival at the examination time. sPD-1 and sPD-L1/L2 serum levels above median were markedly related to a decreased probability of 5-years OS in patients with HNCs. The sPD-1 and sPD-L1/2 were complementary markers representing clinical condition and illness outcomes for HNCs patients. The sPD-L1 might accelerate the characterization of high-risk patients with disapproving illness outcomes. sPD-1 and sPD-L1/2 could be easily accessed through liquid biopsy. The incorporation of them as indicators for risk evaluation throughout treatment scheduling and follow-up seems to be an appreciated method.

Sex-dependent PD-L1/sPD-L1 trafficking in human endothelial cells in response to inflammatory cytokines and VEGF.

Programmed cell death 1 ligand 1 (PD-L1) expressed in non-immune cells is involved in immune-mediated tissue damage in the context of inflammatory conditions and tumor immune escape. Emerging evidence suggests soluble (s)PD-L1 as a marker of inflammation. Based on well-established sex-specific differences in immunity, we tested the novel hypotheses that (i) endothelial cell PD-L1 is modulated by inflammatory cytokines and vascular endothelial growth factor (VEGF) in a sex-specific fashion, and (ii) the endothelium is a source of sPD-L1. After exposure of human umbilical vein endothelial cells (HUVECs) to lipopolysaccharide, interleukin (IL)1ß or VEGF for 24 h, total PD-L1 levels were upregulated solely in cells from female donors, while being unchanged in those from male donors. Accordingly, exposure to synovial fluids from patients with inflammatory arthritis upregulated PD-L1 levels in HUVECs from female donors only. Membrane PD-L1 expression as measured by flow cytometry was unchanged in response to inflammatory stimuli. However, exposure to 2 ng/mL IL-1ß or 50 ng/mL VEGF time-dependently increased sPD-L1 release by HUVECs from female donors. Treatment with the metalloproteinase (MMP) inhibitor GM6001 (10 µM) prevented IL-1ß-induced sPD-L1 release and enhanced membrane PD-L1 levels. The anti-VEGF agents bevacizumab and sunitinib reduced both VEGF-induced PD-L1 accumulation and sPD-L1 secretion. Thus, inflammatory agents and VEGF rapidly increased endothelial PD-L1 levels in a sex-specific fashion. Furthermore, the vascular endothelium may be a sPD-L1 source, whose production is MMP-dependent and modulated by anti-VEGF agents. These findings may have implications for sex-specific immunity, vascular inflammation and response to anti-angiogenic therapy.

Association between response to anti-PD-1 treatment and blood soluble PD-L1 and IL-8 changes in patients with NSCLC.

In this study, we explored the dynamic changes in blood sPD-L1 and its clinical value during anti-PD-1 immunotherapy in non-small cell lung cancer (NSCLC) patients. First, we established a sandwich ELISA for functional sPD-L1 that can bind to PD-1 and has biological functions. By monitoring functional sPD-L1 in 39 NSCLC patients treated with anti-PD-1 antibodies, we found a positive correlation between baseline sPD-L1 and tissue PD-L1 (P = 0.0376, r = 0.3581), with patients with lymph node metastasis having higher sPD-L1 levels (P = 0.0037) than those without lymph node metastasis. Although baseline functional sPD-L1 and PFS did not correlate significantly in this study, changes in sPD-L1 in patients with different clinical responses showed different trends. Blood sPD-L1 increased in 93% of patients after two cycles of anti-PD-1 treatment (P = 0.0054); sPD-L1 in nonresponsive patients continued to increase (P = 0.0181), but sPD-L1 started to decline in responsive patients. Blood IL-8 levels were associated with tumor load, and when combined with IL-8, the evaluation accuracy of sPD-L1 improved to 86.4%. This study preliminarily shows that the combination of sPD-L1 and IL-8 is a convenient and effective method for monitoring and evaluating the effectiveness of anti-PD-1 immunotherapy in NSCLC patients.

Prognostic and predictive role of soluble programmed death ligand-1 in head and neck cancer.

OBJECTIVES: The aim of the study was to investigate clinical significance of soluble PD-L1 (sPD-L1) serum level in head and neck cancer and to evaluate its role as a possible prognostic and predictive biomarker. METHODS: A prospective analysis of sPD-L1 levels in 60 patients diagnosed and treated due to malignant and non-malignant lesions in the region of head and neck was performed in peripheral blood by an ELISA test. RESULTS: The range of sPD-L1 in the study group was 0.16-1.63ng/mL, mean 0.64±0.32. There were no differences in the mean sPD-L1 regarding patients' age, sex, and the localization of the lesion. Statistically significant difference was revealed in the average sPD-L1 level (p= 0.006) depending on the histopathological advancement of the lesions, 0.704 ± 0.349 and 0.512 ± 0.177 respectively in the malignant and benign group. The separate analysis of laryngeal lesions confirmed statistical difference in sPD-L1 (p= 0.002) for the malignant lesions (0.741 ± 0.353) compared with the benign (0.489 ± 0.175). The sPD-L1 level of 0.765 ng/mL or higher, revealed 35% sensitivity and 95.5% specificity for the diagnosis of head and neck malignant lesions (AUC=0.664, 95% CI 0.529‒0.8, p-value=0.039). The 1-year DFS was 83.3% in the group of patients with low sPD-L1 levels (< 0.765ng/mL) and 53.8% in patients with high sPD-L1 (≥0.765ng/mL). The 2-year OS were 68% and 69.2% respectively in both groups. The log-rank test confirmed statistically significant prognostic value of sPD-L1 level for 1-year DFS (p-value=0.035). CONCLUSIONS: sPD-L1 is a promising prognostic and early recurrence predictive biomarker for head and neck cancers, most significantly for laryngeal lesions.

Soluble programmed death ligand-1-induced immunosuppressive effects on chimeric antigen receptor-natural killer cells targeting Glypican-3 in hepatocellular carcinoma.

Although the pre-clinical study of chimeric antigen receptor (CAR)-natural killer (NK) cell was effective against various tumours, immunosuppression mediated by tumour microenvironment hampers their application and several efforts have been explored to improve their effect in combating solid tumours. Glypican 3 (GPC3) is a promising target for hepatocellular carcinoma (HCC), and CAR-T cells targeting GPC3 have been tested in clinical trials. Based on an affinity-enhanced antibody (hYP7) targeting GPC3, we constructed GPC3-CAR-NK cells to explore their potential function in the treatment of HCC. We found that patients with HCC secreted high levels of soluble programmed death-ligand 1 (sPD-L1), which inhibits the function of CAR-NK cells targeting GPC3. In addition, we combined high-affinity sPD-L1 variant (L3C7c-Fc) with GPC3-CAR-NK cells to solve the problem of GPC3-CAR-NK inhibition. Our studies demonstrated that L3C7c-Fc could enhance the therapeutic effect of CAR-NK cells by reversing the suppression of sPD-L1, which provides the experimental evidence for the subsequent development of HCC immunotherapy strategies.

Soluble PD-L1: a potential dynamic predictive biomarker for immunotherapy in patients with proficient mismatch repair colorectal cancer.

BACKGROUND: Circulating soluble programmed death ligand 1 (sPD-L1) can negatively regulate T-cell function and serve as a prognostic or predictive marker in a variety of cancers. However, rare studies have evaluated the potential roles of sPD-L1, and no study has estimated its predictive value for the efficacy of immune treatment in colorectal cancer (CRC). METHODS: Plasma samples from 192 CRC patients were used to estimate correlations between clinicopathological features and sPD-L1, secreted PD-L1 (secPD-L1) and exosomal PD-L1 (exoPD-L1). Baseline and posttreatment sPD-L1 levels were also investigated in 55 patients with metastatic CRC (mCRC) treated with chemotherapy ± targeted therapy and 40 patients with proficient mismatch repair (pMMR) mCRC treated with combination immunotherapy. Both sPD-L1 and secPD-L1 were quantified by enzyme-linked immunosorbent assay, while exoPD-L1 was analyzed using flow cytometry. RESULTS: secPD-L1 was the major component and positively correlated with sPD-L1 in CRC, while exoPD-L1 was almost undetectable. Higher levels of sPD-L1 were detected in patients with distant metastasis, especially those with distant lymph node metastasis and tissue combined positive score (CPS) instead of tumor proportion score (TPS). Chemotherapy or targeted therapy did not significantly impact sPD-L1 concentration. Progressive disease on combination immunotherapy was associated with an increase in sPD-L1 level, whereas no significant change was observed in patients with durable clinical benefit. CONCLUSION: sPD-L1 mainly consisted of secPD-L1, and its level was higher in patients with distant metastasis, especially distant lymph node metastasis and positive CPS. sPD-L1 is a potential dynamic marker to identify rapid progression on combination immunotherapy and avoid ineffective treatment for pMMR CRC.

The correlation of serum sPD-1 and sPD-L1 levels with clinical, pathological characteristics and lymph node metastasis in nonsmall cell lung cancer patients.

BACKGROUND: Significant advances have been achieved in immunotherapy for the treatment of lung cancer. It is known that tumor cells and cells in the tumor microenvironment express high amounts of programmed cell death ligand 1 (PD-L1). These PD-L1s interact with programmed cell death protein 1 (PD-1), causing immunosuppression. The aim of our study is to examine the correlation between the serum sPD-1 and sPD-L1 levels and clinicopathological characteristics in patients with nonsmall cell lung cancer. We also compared our results with the healthy population (control group). METHODS: Thirthy-seven nonsmall cell lung cancer (NSCLC) patients who were operated in our clinic were included in our study. The control group included fifteen healthy patients. The sPD-1 and sPD-L1 levels were measured in serum samples by using the ELISA method. RESULTS: The preoperative sPD-1 and sPD-L1 levels were significantly higher in the study group compared to the control group (44.12 ± 22.25 pg/mL vs. 18.54 ± 6.56 pg/mL; p = 0.001 and 26.15 ± 18.03 pg/mL vs. 10.29 ± 3.08 pg/mL; p = 0.001, respectively). There was a statistically significant decline in serum sPD-1 and sPD-L1 levels at the preoperative and postoperative 1st, 7th, and 30th days following surgical resection (44.12 ± 22.25 pg/mL, 37.86 ± 18.02 pg/mL, 36.33 ± 18.36 pg/mL, 34.14 ± 13.71 pg/mL; p = 0.007 and 26.15 ± 18.03 pg/mL, 20.60 ± 15.50 pg/mL, 18.31 ± 14.04 pg/mL, 13.64 ± 10.60 pg/mL; p = 0.001, respectively).There was a positive correlation between the preoperative and postoperative 30th day serum sPD-1 levels and the tumor size (p = 0.031, r = 0.352; p = 0.024, r = 0.371; respectively). We also found a positive correlation between the preoperative and postoperative 30th day serum sPD-L1 levels and pleural invasion (p = 0.001, p = 0.001; respectively), and the N category (p = 0.015, p = 0.013; respectively). DISCUSSION: We think that sPD-1 and sPD-L1 levels may be used as a potential biomarker for lung cancer screening, prediction of the stage, and besides to detect recurrences and/or metastases following resection in NSCLC following validation with multicenter and larger-scale prospective trials.