Soluble Programmed Cell Death Ligand 1 as a Novel Biomarker for Nivolumab Therapy for Non-Small-cell Lung Cancer

BACKGROUND

Biomarkers for predicting the effect of anti-programmed cell death 1 (PD-1) monoclonal antibody against non-small-cell lung cancer (NSCLC) are urgently required. Although it is known that the blood levels of soluble programmed cell death ligand 1 (sPD-L1) are elevated in various malignancies, the nature of sPD-L1 has not been thoroughly elucidated. We investigated the significance of plasma sPD-L1 levels as a biomarker for anti-PD-1 monoclonal antibody, nivolumab therapy.

PATIENTS AND METHODS

The present prospective study included 39 NSCLC patients. The patients were treated with nivolumab at the dose of 3 mg/kg every 2 weeks, and the effects of nivolumab on NSCLC were assessed according to the change in tumor size, time to treatment failure (TTF), and overall survival (OS). The baseline plasma sPD-L1 concentration was determined using an enzyme-linked immunosorbent assay.

RESULTS

The area under the curve of the receiver operating characteristic curve was 0.761. The calculated optimal cutoff point for sPD-L1 in the plasma samples was 3.357 ng/mL. Of the 39 patients, 59% with low plasma sPD-L1 levels achieved a complete response or partial response and 25% of those with high plasma sPD-L1 levels did so. In addition, 22% of the patients with low plasma sPD-L1 levels developed progressive disease compared with 75% of those with high plasma sPD-L1 levels. The TTF and OS were significantly longer for those patients with low plasma sPD-L1 levels compared with the TTF and OS for those with high plasma sPD-L1 levels.

CONCLUSION

The clinical benefit from nivolumab therapy was significantly associated with the baseline plasma sPD-L1 levels. Plasma sPD-L1 levels might represent a novel biomarker for the prediction of the efficacy of nivolumab therapy against NSCLC.

Immune checkpoint molecules soluble program death ligand 1 and galectin-9 are increased in pregnancy

PROBLEM

Pregnancy requires balance between tolerance to the haploidentical fetus and the mother's ability to mount immune responses. There are parallels to this phenomenon that occur in metastatic cancer. We assessed soluble program death ligand-1 soluble PD-L1 (sPD-L1) and galectin-9 in the blood of pregnant women during gestation as these molecules are highly involved in immune suppression during cancer.

METHOD OF STUDY

Maternal blood was collected from 30 primigravida women at monthly intervals during pregnancy, delivery and 6-week post-partum. Blood was analyzed for sPD-L1 and galectin-9 concentrations by ELISA. Term placentas were collected in formalin and IHC was completed for PD-L1 and galectin-9 expression.

RESULTS

Maternal blood levels of sPD-L1 (0.438 ng/mL) and galectin-9 (1976 pg/mL) were elevated early in normal pregnancies compared to non-pregnant controls (0.242 ng/mL and 773 pg/mL, respectively). sPD-L1 increased throughout gestation, whereas galectin-9 remained elevated until parturition; both proteins returned to control levels post-partum. Women carrying male fetuses had significantly higher galectin-9 levels, but not sPD-L1, than those carrying females (2263 pg/mL vs 1874 pg/mL; P = .0005). Trophoblast cells of the term placenta coexpress galectin-9 and PD-L1.

CONCLUSION

Immune-regulatory molecules galectin-9 and sPD-L1 increased during pregnancy and may play a role in immune tolerance that is critical for the fetus.

ADAM10 and ADAM17 cleave PD-L1 to mediate PD-(L)1 inhibitor resistance

ADAM10 and ADAM17 expression and soluble PD-L1 (sPD-L1) predict poor prognosis in many malignancies, including in patients treated with PD-(L)1 inhibitors. The mechanism of soluble PD-L1 production and its effects are unknown. Here we uncover a novel mechanism of ADAM10- and ADAM17-mediated resistance to PD-(L)1 inhibitors. ADAM10 and ADAM17 cleave PD-L1 from the surface of malignant cells and extracellular vesicles. This cleavage produces an active sPD-L1 fragment that induces apoptosis in CD8 + T cells and compromises the killing of tumor cells by CD8 + T cells. Reduced tumor site PD-L1 protein-to-mRNA ratios predict poor outcomes and are correlated with elevated ADAM10 and ADAM17 expression in multiple cancers. These results may explain the discordance between PD-L1 immunohistochemistry and PD-(L)1 inhibitor response. Thus, including ADAM10 and ADAM17 tissue staining may improve therapy selection. Furthermore, treatment with an ADAM10/ADAM17 inhibitor may abrogate PD-(L)1 inhibitor resistance and improve clinical responses to PD-(L)1 immunotherapy.

Soluble forms of PD-L1 and PD-1 as prognostic and predictive markers of sunitinib efficacy in patients with metastatic clear cell renal cell carcinoma

Metastatic clear cell renal cell carcinoma (mccRCC) benefits from several treatment options in the first-line setting with VEGFR inhibitors and/or immunotherapy including anti-PD-L1 or anti-PD1 agents. Identification of predictive biomarkers is highly needed to optimize patient care. Circulating markers could reflect the biology of metastatic disease. Therefore, we evaluated soluble forms of PD-L1 (sPD-L1) and PD-1 (sPD-1) in mccRCC patients. The levels of sPD-L1 and sPD-1 were evaluated from plasma samples of mccRCC patients before they received a first-line treatment (T0) by the VEGFR inhibitor sunitinib (50 patients) or by the anti-VEGF bevacizumab (37 patients). The levels of sPD-L1 and sPD-1 were correlated to clinical parameters and progression-free survival (PFS). High levels of sPD-1 or sPDL1 were not correlated to PFS under bevacizumab while they were independent prognostic factors of PFS in the sunitinib group. Patients with high T0 plasmatic levels of sPD-L1 had a shorter PFS (11.3 vs 22.5 months, p = .011) in the sunitinib group. Equivalent shorter PFS was found with high levels of sPD-1 (8.6 vs 14.1 months, p = .009). mccRCC patients with high plasmatic levels of sPD-L1 or sPD-1 are poor responders to sunitinib. sPD-L1 or sPD-1 could be a valuable tool to guide the optimal treatment strategy including VEGFR inhibitor.

Elevated levels of soluble PD-L1 are associated with reduced recurrence in papillary thyroid cancer

To date, no research evaluating the predictive capabilities of soluble programmed cell death-ligand 1 (sPD-L1) in thyroid cancer patients has been performed. We aimed to investigate the prognostic significance of sPD-L1 expression in papillary thyroid cancer (PTC) and to evaluate the association between sPD-L1 levels with tumoural PD-L1 expression and patient outcomes. Pre-treatment levels of serum and plasma sPD-L1 were measured by ELISA in 101 PTC patients. Tissue microarrays were stained with an anti-PD-L1 antibody, clone SP263 (Ventana). The median serum sPD-L1 concentration in PTC patients was significantly higher compared to healthy controls (P = 0.028). An increased incidence of extrathyroidal extension was significantly associated with an elevated serum sPD-L1 level (P = 0.015). Patients with high serum sPD-L1 levels had significantly shorter median disease-free survival (DFS) as compared to those with low sPD-L1 levels (P = 0.011). Following multivariate analysis, serum sPD-L1 was the only statistically significant predictor for DFS. Patients with both positive serum and tumoural PD-L1 expression had a significantly shorter DFS than those in any other subgroup (P = 0.007). Our study is the first to confirm that sPD-L1 concentration is significantly associated with patient outcome in PTC. Soluble PD-L1 may provide clinicians with a non-invasive biomarker that can lessen dependence on tissue biopsies and diagnose aggressive thyroid cancers at a more treatable stage.

Accumulation of blood-circulating PD-L1-expressing M-MDSCs and monocytes/macrophages in pretreatment ovarian cancer patients is associated with soluble PD-L1

BACKGROUND

Previous studies have shown clinical relevance of programmed death-ligand 1 (PD-L1) and soluble PD-L1 (sPD-L1) in human cancers. However, still contradictory results exist. Our aim was evaluation of PD-L1-expressing monocytic myeloid-derived suppressor cells (M-MDSCs), monocytes/macrophages (MO/MA), tumour cells (TC) and immune/inflammatory cells (IC) as well as investigation of the sPD-L1 in ovarian cancer (OC) patients.

METHODS

The group of 74 pretreatment women were enrollment to the study. The expression of PD-L1 on M-MDSCS and MO/MA was assessed by flow cytometry. The profile of sPD-L1 was examined with ELISA. The expression of PD-L1 in mononuclear cells (MCs) was analyzed using real time PCR. PD-L1 immunohistochemical analysis was prepared on TC and IC. An in silico validation of prognostic significance of PD-L1 mRNA expression was performed based microarray datasets.

RESULTS

OC patients had significantly higher frequency of MO/MA versus M-MDSC in the blood, ascites and tumour (each p < 0.0001). In contrast, PD-L1 expression was higher on M-MDSCs versus MO/MA in the blood and ascites (each p < 0.0001), but not in the tumour (p > 0.05). Significantly higher accumulation of blood-circulating M-MDSC, MO/MA, PD-L1⁺M-MDSC, PD-L1⁺MO/MA and sPD-L1 was observed in patients versus control (p < 0.001, p < 0.05, p < 0.001, p < 0.001 and p < 0.0001, respectively). Accumulation of these factors was clinicopathologic-independent (p > 0.05). The expression of PD-L1 was significantly higher on IC versus TC (p < 0.0001) and was clinicopathologic-independent (p > 0.05) except higher level of PD-L1⁺TC in the endometrioid versus mucinous tumours. Interestingly, blood-circulating sPD-L1 positively correlated with PD-L1⁺M-MDSCs (p = 0.03) and PD-L1⁺MO/MA (p = 0.02) in the blood but not with these cells in the ascites and tumours nor with PD-L1⁺TC/IC (each p > 0.05). PD-L1 and sPD-L1 were not predictors of overall survival (OS; each p > 0.05). Further validation revealed no association between PD-L1 mRNA expression and OS in large independent OC patient cohort (n = 655, p > 0.05).

CONCLUSIONS

Although PD-L1 may not be a prognostic factor for OC, our study demonstrated impaired immunity manifested by up-regulation of PD-L1/sPD-L1. Furthermore, there was a positive association between PD-L1⁺ myeloid cells and sPD-L1 in the blood, suggesting that sPD-L1 may be a noninvasive surrogate marker for PD-L1⁺myeloid cells immunomonitoring in OC. Overall, these data should be under consideration during future clinical studies/trials.

Soluble sPD-L1 and Serum Amyloid A1 as Potential Biomarkers for Lung Cancer

Background

The objective of this prospective study was to evaluate whether soluble programmed cell death-1/programmed cell death-ligand 1 (PD-1/PD-L1) and serum amyloid A1 (SAA1) are potential diagnostic, predictive or prognostic biomarkers in lung cancer.

Methods

Lung cancer patients (n=115) with advanced metastatic disease, 101 with non-small cell lung cancer, NSCLC (77 EGFR wild-type NSCLC patients on chemotherapy, 15 EGFR mutation positive adenocarcinoma patients, 9 patients with mPD-L1 Expression ≥50% NSCLC – responders to immunotherapy), and 14 patients with small cell lung cancer (SCLC) were examined. ELISA method was used to determine sPD-L1 and SAA1 concentrations in patients’ plasma.

Results

Significantly higher blood concentrations of sPD-L1 and SAA1 were noted in lung cancer patients compared with a healthy control group. In PD-L1+ NSCLC patients, a significantly higher sPD-L1 level was noticed compared to any other lung cancer subgroup, as well as the highest average SAA1 value compared to other subgroups.

Conclusions

It seems that sPD-1/PD-L1 might be a potential biomarker, prognostic and/ or predictive, particularly in patients treated with immunotherapy. Serum amyloid A1 has potential to act as a good predictor of patients’ survival, as well as a biomarker of a more advanced disease, with possibly good capability to predict the course of disease measured at different time points.

High Serum PD-L1 Levels Are Associated with Poor Survival in Urothelial Cancer Patients Treated with Chemotherapy and Immune Checkpoint Inhibitor Therapy

Serum PD-L1 (sPD-L1) levels are associated with prognosis in various tumors but has not yet been investigated in advanced bladder cancer. We assessed pretreatment serum samples from 83 BC patients who received platinum chemotherapy and from 12 patients who underwent immune checkpoint inhibitor (ICI) therapy. In addition, on-treatment samples from further therapy cycles were collected during chemotherapy (n = 58) and ICI therapy (n = 11). Serum PD-L1 levels were determined using ELISA. High baseline sPD-L1 levels were associated with worse ECOG status (p = 0.007) and shorter overall survival for both chemotherapy- and ICI-treated patients (p = 0.002 and p = 0.040, respectively). Multivariate analysis revealed high baseline sPD-L1 level as an independent predictor of poor survival for platinum-treated patients (p = 0.002). A correlation analysis between serum concentrations of PD-L1 and matrix metalloprotease-7 (MMP-7)-a protease which was recently found to cleave PD-L1-revealed a positive correlation (p = 0.001). No significant sPD-L1 changes were detected during chemotherapy, while in contrast we found a strong, 25-fold increase in sPD-L1 levels during atezolizumab treatment. In conclusion, our work demonstrates that pretreatment sPD-L1 levels are associated with a poor prognosis of BC patients undergoing platinum and ICI therapy. Future research should prospectively address the value of sPD-L1 in predicting treatment response.

Plasma soluble programmed death ligand 1 levels predict clinical response in peripheral T-cell lymphomas

Immune checkpoints, including PD-1/PD-L1, play an important role in immunosuppression in various malignancies. Elevated levels of soluble programmed death ligand 1 (sPD-L1) are associated with worse prognosis in multiple myeloma and diffuse large B cell lymphoma. Herein, the purpose of this study is to investigate the relationships between plasma sPD-L1 levels and clinical response in peripheral T-cell lymphoma (PTCL) patients. A total of 37 PTCL patients and 20 healthy volunteers were enrolled. Peripheral blood from patients was collected prior to systemic therapy. Plasma levels of sPD-L1 and IFN-γ were measured by enzyme-linked immunosorbent assay (ELISA). PD-L1 expression in tissues was detected by immunohistochemistry (IHC). Clinical response for patients was evaluated. ONCOMINE database analyses showed that PD-L1 mRNA expression was significantly upregulated in PTCLs. The median sPD-L1 level was 0.729 ng/mL for 20 healthy volunteers and 1.696 ng/mL for 37 PTCL patients which was significantly higher than that in healthy volunteers (0.000). The sPD-L1 level was positively correlated with IFN-γ level (0.000, r = 0.849) and was also positively associated with clinical staging (0.045), LDH level (0.003), and β2-MG level (0.045). Patients with high sPD-L1 level had lower overall response rate than those with low sPD-L1 level (88.9% vs 50.0%, 0.022) and tended to have poorer PFS and OS. PD-L1 expression in tissues matched very well with the sPD-L1 level in PTCL patients. In conclusion, PTCL patients had higher sPD-L1 level compared with healthy volunteers. High sPD-L1 level was correlated with worse clinical response, suggesting that sPD-L1 level was an underlying plasma biomarker to predict the prognosis for PTCL patients.

High intensity interval exercise increases the frequency of peripheral PD-1+ CD8+ central memory T-cells and soluble PD-L1 in humans

Exercise can exert anti-inflammatory effects in an intensity-dependent manner; however, the mechanisms mediating these effects are continually being established. Programme Death Receptor-1 (PD-1) is a membrane bound receptor that maintains immune tolerance by dampening immune cell interactions, such as those mediated by cytotoxic T-cell lymphocytes (CD8⁺). The aim of this study was to characterise sub-populations of CD8⁺ T-cells with regards to their expression of PD-1 before and immediately after exercise. Interleukin (IL)-6, soluble PD-1 (sPD-1) and its ligand (sPD-L1) were also quantified in plasma. Eight individuals (mean ​± ​SD: age 29 ​± ​5 years; BMI 24.2 ​± ​3.4 ​kg ​m²; V˙O_2max 44.5 ​± ​6.4 ​ml ​kg⁻¹·min⁻¹) undertook two time and energy-matched cycling bouts in a counterbalanced study design: one of moderate intensity (MOD) and a bout of high intensity interval exercise (HIIE). Both MOD and HIIE increased the number, but not the proportion of circulating CD8⁺ PD-1+ cells, with no differences between trials. Within the CD8⁺ PD-1+ pool, the expression of PD-1 increased on central memory cells following HIIE only (fold change: MOD 1.0 vs HIIE +1.4), as well the concentration of CD8+PD-1+ memory cells within the circulation (cells/uL: MOD -0.4 vs HIIE +5.8). This response composed a very small part of the exercise-induced CD8⁺ lymphocytosis (Pre-Ex: 0.38% to Post-Ex: 0.69%; p ​> ​0.05). sPD-L1 and IL-6 concentration increased in tandem following MOD and HIIE (r ​= ​0.57; P ​= ​0.021), with a reciprocal decline in sPD-1 observed. The current data demonstrate that PD-1+ CD8⁺ lymphocytes were mobilised following both MOD and HIIE. Both the number of central memory CD8⁺ T-cells expressing PD-1 and the expression level on these cells were increased following HIIE only. This intensity-dependent phenotypic response, in conjunction with increased circulatory sPD-L1 may represent an aspect of the anti-inflammatory response to exercise and warrants further investigation.

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PD-1 is a membrane-bound T-cell receptor that regulates immune tolerance.

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We explored phenotypic changes in PD-1+ T-cells after exercise.

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Circulating PD-1+ CD8⁺ T-cells increased after moderate and high intensity interval exercise (HIIE).

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Central memory CD8⁺ T-cell number and expression increased after HIIE only.

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Post-exercise levels of soluble PD-1 Ligand increased and correlated with IL-6.

Soluble Ligand of the Immune Checkpoint Receptor (sPD-L1) in Blood Serum of Patients with Renal Cell Carcinoma

The content of the soluble ligand of the immune checkpoint receptor (sPD-L1) was determined in the blood serum of 106 patients with renal cell carcinoma and 11 patients with benign kidney tumors by direct ELISA (Human sPD-L1 Platinum ELISA; Affimetrix, eBioscience). The control group included 19 healthy men and 18 women. Serum level of sPD-L1 significantly surpassed the control values in both patients with primary renal cancer (p<0.0001) and in patients examined during disease progression (p<0.05). In patients with benign kidney tumors, the level of this marker was significantly higher than in the control (p<0.05), but lower than in patients with renal cell carcinoma. The sPD-L1 level significantly increased with disease stage (p<0.001); it was higher in the presence of metastases in regional lymph nodes irrespective of their number (N1 or N2) than in the absence of metastases (N0); it was also increased in patients with distant metastases (M1) and patients with grade III-IV tumors in comparison with grade III-IV tumors (p<0.05). The highest sPD-L1 levels were recorded in patients with tumor size corresponding to T2 and T3 and decreased in patients with T4 tumors. Thus, sPD-L1 level in patients with renal cell carcinoma correlated with tumor grade and metastasizing and can be considered as a promising marker in monitoring of the effect of anti-PD1/PD-L1 therapy.

Plasma soluble PD-L1 and STAT3 predict the prognosis in diffuse large B cell lymphoma patients

Purpose: Diffuse large B cell lymphoma (DLBCL) is one of the most common B cell lymphomas, which displays heterogeneous pathologies. Programmed cell death 1/ programmed cell death ligand 1 (PD-1/PD-L1) plays an essential role in immunosuppression in multiple malignancies. Signal transducer and activator of transcription 3 (STAT3)-positive patients also have an independently inferior clinical outcome. However, there are no reports on the effect of plasma soluble PD-L1 (sPD-L1) combined with plasma STAT3 on the prognosis of DLBCL. In this study, we investigate the relationships between plasma sPD-L1 combined with STAT3 and clinical prognosis of DLBCL.

Methods: Levels of plasma sPD-L1 and STAT3 were quantified using ELISA in eighty-seven DLBCL patients. Multiplexed immunofluorescence staining was performed to visualize the expression of PD-L1 in twenty-nine matched FFPE specimens from all patients.

Results: The survival analysis revealed that the progression-free survival (PFS) and overall survival (OS) in high sPD-L1 level group were poorer than that in low sPD-L1 level group (PFS, P < 0.001; OS, P < 0.001). Similarly, the PFS and OS in high STAT3 level group were also poorer than that in low STAT3 level group. Multivariate cox regression analysis showed that both high sPD-L1 and high STAT3 levels were the independent prognostic factors negatively affecting survival. In addition, patients with DLBCL having high levels of both sPD-L1 and STAT3 had a worse outcome than those patients having any one high or low levels of both (P < 0.001).

Conclusions: We therefore revealed that high levels of plasma sPD-L1 and STAT3 are associated with inferior outcome for DLBCL patients, suggesting that combined measurement of their levels in plasma may be a promising prognostic strategy for DLBCL patients.

Maternal soluble PD-1 levels are significantly increased in women with preeclampsia

PROBLEM

Programmed cell death-1 (PD-1) and its ligand (PD-L1) have emerged as key players in regulating immune tolerance. Preeclampsia is associated with maladaptation of immune tolerance during pregnancy. This study aimed to determine if maternal soluble PD-1 (sPD-1) and soluble PD-L1 (sPD-L1) levels are altered in preeclampsia.

METHOD OF STUDY

Maternal sPD-1 and sPD-L1 levels were measured by ELISA in 172 pregnant women (86 normotensive and 86 preeclampsia). The differences in sPD-1 and sPD-L1 levels between normotensive and preeclamptic pregnant women, <34 vs >34 weeks, and fetal gender differences were assessed. Data were analyzed by unpaired t test or chi-square. A probability level of <.05 was considered statistically significant.

RESULTS

Maternal sPD-1 levels were significantly higher in preeclamptic than in normotensive pregnant women, 6262 ± 1860 vs 1134 ± 349 pg/mL, P < .01. sPD-1 levels were not statistically different between <34 and >34 weeks of gestation in both normotensive and preeclamptic groups. sPD-1 levels were relatively higher in mothers with female fetus than with male fetus in the preeclamptic group: 8104 ± 3054 vs 3802 ± 2177 pg/mL, but relatively lower in mothers with female fetus than with male fetus in the normotensive group: 425 ± 134 vs 625 ± 182 pg/mL. Maternal sPD-L1 levels were relatively higher in preeclamptic than in normotensive pregnant women: 143 ± 52 vs 69 ± 13 pg/mL.

CONCLUSION

Aberrant sPD-1/sPD-L1 signaling is present in preeclampsia. Whether increased maternal sPD-1 and sPD-L1 levels were associated with fetal gender difference or immune tolerance dissimilarity during pregnancy in women with preeclampsia warrants further investigation.

Epstein-Barr Virus LMP1 Induces Soluble PD-L1 in Nasopharyngeal Carcinoma

Nasopharyngeal carcinoma (NPC) is an Epstein–Barr virus (EBV)-associated malignancy. The principal oncogene of EBV, latent membrane protein 1 (LMP1), induces the expression of programmed death-ligand 1 (PD-L1), which is an immunosuppressive transmembrane protein and a promising therapeutic target for various malignancies. Recent studies have revealed an association between the level of soluble PD-L1 (sPD-L1) and disease progression. However, the role of sPD-L1 in NPC or its relevance to LMP1 has not been elucidated. This study aimed to examine whether LMP1 induces sPD-L1 in vitro and analyze the clinical relevance of LMP1, PD-L1, and sPD-L1 in NPC patients. Analysis of nasopharyngeal cell lines revealed that LMP1 induces both cellular PD-L1 and sPD-L1. Analysis of biopsy specimens from 32 NPC patients revealed that LMP1 expression was significantly correlated with PD-L1 expression. Finally, the serum sPD-L1 level in NPC patients was higher than that in the controls. Moreover, the sPD-L1 level in the advanced stage was higher than that in the early stage. However, LMP1 expression, PD-L1 expression, and sPD-L1 levels were not associated with prognosis. These results suggest that LMP1 induces both sPD-L1 and PD-L1, which are associated with NPC progression.

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.

Serum-soluble PD-L1 may be a potential diagnostic biomarker in sepsis

To investigate whether serum-soluble PD-L1 (sPD-L1) is a potential biomarker for identifying sepsis. This study enrolled 64 septic patients, 29 patients with acute appendicitis, 33 patients with acute pancreatitis and 30 healthy volunteers. Sepsis was defined according to the Sepsis 3.0 criteria.[1] The associated clinical parameters were recorded, blood samples were collected on the first day of diagnosis, and serum sPD-L1 levels were measured using enzyme-linked immunosorbent assays. Compared with the control group, a significant increase in sPD-L1 levels was observed in patients with sepsis (n = 64). Increased sPD-L1 expression correlated strongly with increased clinical inflammatory values (CRP, PCT and WBC) and decreased immunological functional parameters (CD3⁺ , CD4⁺ and CD8⁺ cell counts). The area under the ROC curve (AUC) for sPD-L1 in combination with the sequential organ failure assessment (SOFA) score was superior to the AUC for either sPD-L1 or SOFA score in regard to the diagnosis of sepsis. sPD-L1 may represent a valuable biomarker for the diagnosis of sepsis.

Prognostic value of soluble programmed cell death-1 (sPD-1) and soluble programmed cell death ligand-1 (sPD-L1) for hepatocellular carcinoma: a systematic review and meta-analysis

BACKGROUND

Preliminary studies have suggested that soluble programmed death-1 (sPD-1) and soluble programmed cell death ligand-1 (sPD-L1) have prognostic implications in many malignant tumors. However, the correlation between sPD-1/sPD-L1 level and prognosis of hepatocellular carcinoma (HCC) is still unclear.

METHODS

We searched several electronic databases from database inception to October 7, 2021. Meta-analyses were performed separately for overall survival (OS), disease-free survival (DFS), recurrence-free survival (RFS), time to progression (TTP), and tumor-free survival (TFS). Random effects were introduced to this meta-analysis. The correlation between sPD-1/sPD-L1 level and prognosis was evaluated using hazard ratios (HRs) with 95% confidence intervals (95%CIs).

RESULTS

A total of 11 studies (1291 patients) were incorporated into this meta-analysis, including seven on sPD-L1, two on sPD-1, and two about both factors. The pooled results showed that high sPD-L1 level was associated with worse OS (HR = 2.46, 95%CI 1.74-3.49, P < 0.001; I² = 31.4, P = 0.177) and poorer DFS/RFS/TTP/TFS of patients with HCC (HR = 2.22, 95%CI 1.47-3.35, P < 0.001; I² = 66.1, P = 0.011), irrespective of method of detection, study type, treatment, cut-off value and follow-up time. In contrast, the level of sPD-1 was not correlated to the OS (HR = 1.19, 95%CI 0.55-2.56, P = 0.657) and DFS/TFS of patients with HCC (HR = 0.94, 95%CI 0.36-2.49, P = 0.906).

CONCLUSION

sPD-L1 rather than sPD-1 could be a good predictor for recurrence and survival after treatment for HCC. More high-quality prospective studies are warranted to assess the prognostic value of sPD-1 or sPD-L1 for HCC.

Soluble PD-L1 in blood correlates positively with neutrophil and negatively with lymphocyte mRNA markers and implies adverse sepsis outcome

Sepsis causes a myriad of immunological reactions that result in life-threatening alterations in the human body. Immunosuppression in sepsis is partly attributed to the programmed death receptor (PD-1) and its associated ligand (PD-L1) via the regulation of lymphocytes and neutrophils. Although the soluble forms of these proteins (i.e., sPD-1 and sPD-L1, respectively) are recognized as possible sepsis biomarkers, their functional implications are yet to be elucidated. Our research assessed the correlation between sPD-1 and sPD-L1 and blood mRNA markers and sepsis outcome. Blood samples of septic patients of urogenital origin versus control patients (both groups: n = 18) were analyzed. Blood serum sPD-1 and sPD-L1 levels were determined using the enzyme-linked immunosorbent assay (ELISA). The whole blood mRNA concentrations of PD-1, PD-L1, neutrophil markers (CEACAM8 and MPO), and T-lymphocyte markers (TCRβ, CD4 and CD8) were determined via reverse transcriptase quantitative PCR (RT-qPCR). sPD-L1 levels were significantly increased in septic patients when compared to the controls, whereas sPD-1 levels were unaltered. Patients with high sPD-L1 levels, as dichotomized to the median, had a significantly shorter survival rate than those with low sPD-L1 levels. The sensitivity/specificity characteristics of sPD-L1 proved significant for sepsis detection. Furthermore, sPD-L1 correlated with the mRNA concentrations of PD-L1, CEACAM, and MPO, as well as major inflammatory markers (C-reactive protein and procalcitonin). However, sPD-L1 negatively correlated with TCRβ, CD4, and CD8 mRNAs. sPD-L1 was found to be significantly increased in septic patients. Notably, sPD-L1 correlated with PD-L1 mRNA and neutrophil markers and was indicative of adverse outcomes.

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.

LEVEL OF EVIDENCE: 3

Key Immune Checkpoint PD-1/PD-L1 Signaling Pathway Components in the Blood Serum from Patients with Bone Tumors

The levels of sPD-1 and sPD-L1 were analyzed in blood serum of 132 patients (age 14-70 years) with primary bone tumors: osteosarcoma (N=39), chondrosarcoma (N=42), Ewing sarcoma (N=9), chordoma (N=12), giant-cell bone tumor (GCBT) (N=16), benign neoplasms (N=14) and in and practically healthy subjects (age 19-58 years; N=27). sPD-L1 levels in all studied bone neoplasms were significantly higher than in the control. Serum sPD-1 level in GCBT patients was significantly higher than in the control, benign neoplasms, chondrosarcoma, and chordoma patients, but did not differ from osteosarcoma group. sPD-1 concentration in Ewing sarcoma was significantly higher than in chordoma and chondrosarcoma, but did not differ from the control. sPD-1 level in chondrosarcoma patients was also lower than in osteosarcoma, Ewing sarcoma, and in the control. Both sPD-1 and sPD-L1 concentrations were not significantly associated with the type of affected bone, process localization, disease stage, tumor histological grade, patients' age and sex. These results suggest the possibility of using these biological markers for preliminary assessment of the character of the process in the bone.

[The content of the soluble forms PD-1 and PD-L1 in blood serum of patients with gastric cancer and their relationship with clinical and morphological characteristics of the disease.]

Results of comparative ELISA investigation of pretreatment sPD-1 and sPD-L1 content in blood plasma of 100 gastric cancer patients at various disease stages aged 25 to 81 years are presented. Control group included 60 practically healthy donors aged 18 - 68 years. Plasma sPD-L1 concentrations did not differ between gastric cancer patients and control group, and sPD-1 levels were statistically significantly lower in patients than in healthy donors (p<0.0001). Positive correlation (R=0.38; p=0.003) was revealed between plasma sPD-1 и sPD-L1 levels in control group and negative (R= -0.26; p=0,009) - in gastric cancer patients. ROC curve revealed the best sPD-1 cut-off level (< 21 pg/ml) with 77% sensitivity and 63.3% specificity, which is not sufficient for its application as diagnostic marker. Statistically significant increase of plasma sPD-L1 from stage I to stage IIIC (R=0.50; p=0.000011) was found. Analysis of associations between the evaluated markers' levels and indices of gastric cancer expansion according to TNM system revealed statistically significant positive associations of plasma sPD -L1 levels with T (tumor invasiondepth) and N (number of affected lymph nodes) indices: R=0.33; p=0.00093, and R=0.27; p=0.0099 respectively. sPD-L1 level was significantly increased in patients with low differentiated adenocarcinoma and cricoid-cell cancer as compared to highly differentiated adenocarcinoma (p=0.02 and p=0.004 respectively); in patients with cricoid-cell cancer it was also higher than in those with moderately differentiated adenocarcinoma (p=0.043) and undifferentiated cancer (p=0.049). Plasma sPD-1 level did not depend on disease stage, TNM system indices and tumor histological structure. Thus, soluble ligand sPD-L1, but not its receptor sPD-1, plasma level is increased in patients with unfavorable clinical and morphological characteristics, may be regarded as potentially valuable prognostic factor for gastric cancer patients' survival, and probably as a predictor of anti - PD-1/PD-L1 treatment efficiency.

Prognostic significance of soluble forms of immune checkpoint PD-1/PDL1 receptor and ligand in blood plasma of gastric cancer patients

Analysis of long-term treatment results of 101 primary gastric cancer patients at various stages of the tumor process followed during 1 - 41 months (median - 6,4 months) from the onset of specific treatment are presented depending on the levels of soluble forms (s) of PD-1 receptor and its ligand PD-L1 in blood plasma. Overall survival assessed by Kaplan-Meyer analysis and with the help of Cox multiparametric regression model was applied as the criterion of prognostic value. It was found that at high (≥ 35 pg/ml) sPD-L1 levels in blood plasma, the overall survival of patients with gastric cancer was statistically significantly lower than at the marker's levels below 35 pg / ml (p <0.045): 1-year survival comprised 78 and 96%, 2-year - 52 and 78%; 3-year - 40 and 61% at high and low sPD-L1 respectively. Median survival of patients with high plasma sPD-L1 comprised 29 months, of those with low sPD-L1 was not achieved during the whole follow-up period. This trend was observed not only in the total group of stage I-IV gastric cancer patients, but also in patients at the early stages of the disease, though sPD-L1 did not show an independent prognostic value in multiparametric model. At the same time, the overall survival of patients with gastric cancer did not depend on the baseline levels sPD-1 in blood plasma. Thus, soluble ligand sPD-L1 can be considered as a potentially valuable factor for prognosis of gastric cancer patients' survival, and, probably, of anti-PD-1/PD-L1 treatment efficiency, but further studies and patients' monitoring are required to prove this statement.

PD-L1, PDK-1 and p-Akt are correlated in patients with papillary thyroid carcinoma

BACKGROUND

Papillary thyroid carcinoma (PTC) is the most common type of thyroid carcinoma.

OBJECTIVES

To investigate the clinical significance of programmed death ligand 1 (PD-L1) and phosphoinositide-dependent protein kinase 1 (PDK1) in PTC.

MATERIAL AND METHODS

A total of 194 PTC patients were recruited. Contralateral normal thyroid tissues were obtained and used as controls (n = 80). The expression levels of PD-L1, PDK1 and p-Akt were determined using immunohistochemistry.

RESULTS

The PD-L1, PDK1 and p-Akt were upregulated in cancer tissues compared to the normal tissues. The mean optical density (MOD) values of PD-L1, PDK1 and p-Akt were significantly higher in the PTC tissues. The expression of PD-L1 positively correlated with the levels of PDK1 and p-Akt. In addition, the expression of PD-L1, PDK1 and p-Akt in PTC patients without chronic lymphocytic thyroiditis (CLT) was significantly higher than the expression of those proteins in the CLT patients. The patients with higher expression levels of PD-L1, PDK1 or p-Akt had remarkably larger tumors and higher rates of TNM III-IV, capsular infiltration, lymph node metastasis, and of recurrence. The Kaplan-Meier curve showed that patients with lower expression of PD-L1, PDK1 or p-Akt had significantly longer recurrence-free time. The logistic regression analysis revealed that only CLT, PD-L and capsular infiltration were risk factors for patients' five-year recurrence.

CONCLUSIONS

The PD-L1, PDK1 and p-Akt were found to be positively correlated with a poor prognosis in PTC.

Prognostic prospect of soluble programmed cell death ligand-1 in cancer management

Aggressive tissue biopsy is commonly unavoidable in the management of most suspected tumor cases to conclusively verify the presence of cancerous cells through histological assessment. The extracted tissue is also immunostained for detection of antigens (tissue tumor markers) of potential prognostic or therapeutic importance to assist in treatment decision. Although liquid biopsies can be a powerful tool for monitoring treatment response, they are still excluded from standard cancer diagnostics, and their utility is still being debated in the scientific community. With a myriad of soluble tissue tumor markers now being discovered, liquid biopsies could completely change the current paradigms of cancer management. Recently, soluble programmed cell death ligand-1 (sPD-L1), which is found in the peripheral blood, i.e. serum and plasma, has shown potential as a pre-therapeutic predictive marker as well as a prognostic biomarker to monitor treatment efficacy. Thus, this review focuses on the emergence of sPD-L1 and promising technologies for its detection in order to support liquid biopsies for future cancer management.