Programmed Cell Death Ligand 1 Expression Levels Research Articles

Abstract P068: Automated cell type specific PD-L1 quantification by artificial intelligence using high throughput bleach & stain 15-marker multiplex fluorescence immunohistochemistry in human cancers

Abstract Introduction: The quantification of PD-L1 (programmed cell death ligand 1) has been used to predict patient's survival, to characterize the tumor immune microenvironment, and to predict response to immune checkpoint therapies. However, a framework to assess the PD-L1 status with a high interobserver reproducibility on tumor cells and different types of immune cells has yet to be established. Methods: To study the impact of PD-L1 expression on the tumor immune microenvironment and patient outcome, a framework for fully automated PD-L1 quantification on tumor cells and immune cells was established and validated. Automated PD-L1 quantification was facilitated by incorporating three different deep learning steps for the analysis of more than 80 different neoplasms from more than 10'000 tumor specimens using a bleach & stain 15-marker multiplex fluorescence immunohistochemistry panel (i.e., PD-L1, PD-1, CTLA-4, panCK, CD68, CD163, CD11c, iNOS, CD3, CD8, CD4, FOXP3, CD20, Ki67, CD31). Clinicopathological parameter were available for more than 30 tumor entities and overall survival data were available for 1517 breast cancer specimens. Results: Comparing the automated deep-learning based PD-L1 quantification with conventional brightfield PD-L1 data revealed a high concordance in tumor cells (p<0.0001) as well as immune cells (p<0.0001) and an accuracy of the automated PD-L1 quantification ranging from 90% to 95.2%. Across all tumor entities, the PD-L1 expression level was significantly higher in distinct macrophage/dendritic cell (DC) subsets (identified by CD68, CD163, CD11c, iNOS; p<000.1) and in macrophages/DCs located in the Stroma (p<0.0001) as compared to intratumoral macrophages/DC subsets. Across all different tumor entities, the PD-L1 expression was highly variable and distinct PD-L1 driven immune phenotypes were identified based on the PD-L1 intensity on both tumor and immune cells, the distance between non-exhausted T-cell subsets (i.e. PD-1 and CTLA-4 expression on CD3+CD8+ cytotoxic T-cells, CD3+CD4+ T-helper cells, CD3+CD4+FOXP3+ regulatory T-cells) and tumor cells as well as macrophage/(DC) subtypes. In breast cancer, the PD-L1 fluorescence intensity on tumor cells showed a significantly higher predictive performance for overall survival with an area under receiver operating curves (AUC) of 0.72 (p<0.0001) than the percentage of PD-L1+ tumor cells (AUC: 0.54). In PD-L1 positive as well as negative breast cancers a close spatial relationship between T- cell subsets (CD3+CD4±CD8±FOXP3±PD-1±CTLA-4±) and Macrophage/DC subsets (CD68±CD163±CD11c±iNOS) was found prognostic relevant (p<0.0001). Conclusion: In conclusion, multiplex immunofluorescence PD-L1 assessment provides cutoff-free/continuous PD-L1 data which are superior to the conventional percentage of PD-L1+ tumor cells and of high prognostic relevance. The combined analysis of spatial PD-L1/PD-1 data and more than 20 different immune cell subtypes of the immune tumor microenvironment revealed distinct PD-L1 immune phenotypes. Citation Format: Niclas C. Blessin, Elena Bady, Tim Mandelkow, Cheng Yang, Jonas B. Raedler, Ronald Simon, Christoph Fraune, Maximilian Lennartz, Sarah Minner, Eike Burandt, Doris Höflmayer, Guido Sauter, Katharina Möller, Sören A. Weidemann. Automated cell type specific PD-L1 quantification by artificial intelligence using high throughput bleach & stain 15-marker multiplex fluorescence immunohistochemistry in human cancers [abstract]. In: Abstracts: AACR Virtual Special Conference: Tumor Immunology and Immunotherapy; 2021 Oct 5-6. Philadelphia (PA): AACR; Cancer Immunol Res 2022;10(1 Suppl):Abstract nr P068.

Effect of baricitinib in regulating programmed death 1 and ligand programmed cell death ligand 1 through JAK/STAT pathway in psoriasis.

OBJECTIVES:Psoriasis is a chronic infectious skin disease triggered by an autoimmune process involving T-cell-mediated hyper-proliferation of keratinocytes. The objective of this study is to assess the modulation of programmed death 1 (PD-1) and its ligand programmed cell death ligand 1 (PD-L1) through JAK/STAT pathway during the development of a psoriasis-like disease by both in vitro and in vivo model. Baricitinib, a known inhibitor of JAK1 and JAK2, was used to study the impact on PD-1 and PD-L1.MATERIALS AND METHODS:Human peripheral blood mononuclear cells (PBMC) were stimulated with either anti-CD3/CD28 or PMA/Ionomycin, to modulate level of PD-1 and PD-L1 under psoriasis-like condition. Interferon-gamma (IFNγ) was used to treat HaCaT cells to mimic the diseased keratinocytes found in Psoriatic patients. Psoriasis was induced with Imiquimod (IMQ) in animal model to study the cross-talk between different cell types and pathways.RESULTS:Expression levels of PD-1 and PD-L1 in PBMC, and secretion of cytokines, namely tumor necrosis factor-α (TNFα), IFNγ, interleukin (IL)-6, and IL-1 β, were down-regulated on treatment with baricitinib. Further, in IFNγ-treated HaCaT cells (keratinocytes) mRNA levels of KRT-17 and PD-L1 were up-regulated.). Interestingly, in IFNγ-treated HaCat cells baricitinib decreased the levels of inflammatory cytokines such as IL-1 β, IL-6, and TNFα along with KRT-17 and PD-L1. On IFNγ-treatment. Data from both PBMC and HaCaT suggest an anti-inflammatory role for this compound. Accordingly, baricitinib was able to alleviate disease symptom in IMQ induce mice model of psoriasis. As a consequence of baricitinib treatment down-regulation of p-STAT3, PD- and PD-L1 expression levels were observed.CONCLUSION:This study demonstrates a crosstalk between JAK/STAT and PD-1/PD-L1 pathways. It also demonstrates that cytokines such as IFNγ and IL-17 are down-regulated by baricitinib. We believe decreased expressions of PD-1 and PD-L1 may be a consequence of baricitinib-induced down-regulation of IFNγ and IL-17. More importantly, our data from the acute model of psoriasis indicates that PD-L1 behaves as a T-cell-associated T-cell-associated surrogate activation marker rather than immunosuppressive marker in early phase of psoriasis. Therefore it does not exhibit a causal relationship to disease.

Identification of circRNAs involved in the development of hepatocellular carcinoma after insufficient radiofrequency ablation.

Previous studies have reported that circular RNAs (circRNAs) play a key role in the pathogenesis and progression of various diseases. In the present study, we aimed to identify potential circRNAs associated with the progression of hepatocellular carcinoma (HCC) after insufficient radiofrequency ablation (IRFA). A xenograft mouse IRFA model was initially established, and immunohistochemical staining (IHC) and polymerase chain reaction (PCR) were performed to confirm the expression of programmed cell death-ligand 1 (PD-L1) and vascular endothelial growth factor receptor-1 (VEGFR-1). CircRNA expression alterations were screened by next-generation sequencing (RNA-seq). Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were conducted to predict the function of genes coding differentially expressed circRNAs. The selected circRNAs were validated utilizing PCR and Sanger sequencing. The relationships between circRNAs, microRNAs, PD-L1, and VEGFR-1 were predicted by bioinformatics. Overall, a total of 612 circRNAs were differentially expressed in IRFA-treated subcutaneous tumorigenesis tissue. Among them, 435 circRNAs were significantly upregulated and 177 circRNAs were downregulated. GO and KEGG analyses were employed to predict the functions of these circRNAs. Thereafter, quantitative reverse transcription PCR (qRT-PCR) assays determined that these seven circRNAs were overexpressed in the IRFA group, which was consistent with the RNA-seq results. Based on the bioinformatic analysis, seven circRNAs confirmed by Sanger sequencing were predicted to likely regulate PD-L1 and VEGFR-1 expression levels by functioning as sponges for microRNAs (miRNAs) and forming a circRNA-miRNA-PD-L1/VEGFR-1 regulatory network. Finally, IHC and qRT-PCR of PD-L1 and VEGFR-1 confirmed the activation of this pathway. Taken together, we report that differentially expressed circRNAs might simultaneously regulate PD-L1 and VEGFR-1 in the IRFA tissues, which provides a novel view of circRNAs in HCC progression after the IRFA procedure.

Expression of miRNA-601 and PD-L1 among Iranian Patients with Lung Cancer and Their Relationship with Smoking and Mycoplasma Infection.

Objective microRNAs (miRNAs) are highly conserved noncoding RNA molecules that mainly function to regulate gene expressions, and have a significant role in tumourigenesis. Programmed cell death-ligand 1 (PD-L1) is a major co-inhibitory checkpoint signal that controls T cell activities, maintains peripheral tolerance and is contribute to the development of cancer. The aim of this study is to examine miRNA-601 and PD-L1 gene expression in patients with non-small-cell lung cancer (NSCLC) and its relation with Mycoplasma infection. Materials and Methods In this case-control study, respiratory secretions and blood samples were collected from 80 healthy people and 80 NSCLC patients. The expression levels of miRNA-601 and PD-L1 were evaluated using real-time polymerase chain reaction (qRT-PCR). The presence of Mycoplasma species in respiratory secretions was detected by biochemical assays and PCR. Results There was no significant difference in the expression level of miRNA-601 between control and patients with tumour stage I, but miRNA-601 expression was significantly downregulated in patients with tumour stages II, III, and IV (P<0.05). A significant, negative relationship was found between miRNA-601 expression and tumour stage (P<0.001). Overexpression of PD-L1 was found in all of the disease stages. PCR results showed the presence of Mycoplasma pneumoniae (M. pneumoniae) in respiratory secretions from patients with stages III and IV NSCLC. We observed that 72% of patients with stages III and IV NSCLC had a positive smoking history and 65.3% were positive for Mycoplasma. ConclusionSerum miRNA-601 may act as a potential noninvasive biomarker for lung cancer and Mycoplasma infection prognosis.

The Prognostic Significance of PD1 and PDL1 Gene Expression in Lung Cancer: A Meta-Analysis.

BackgroundImmune checkpoint blockade therapy represents an extraordinary advance in lung cancer treatment. It is important to determine the expression of immune checkpoint genes, such as programmed cell death 1 (PD1) and programmed cell death-ligand 1 (PDL1), to develop immunotherapeutic strategies. The aim of this study was to explore the association between PD1 and PDL1 gene expression and prognoses and outcomes in lung cancer.MethodsThis meta-analysis analyzed 1,251 patients from eight different microarray gene expression datasets and were evaluated for their prognostic implications and verified using another independent research.ResultsThe mean expression levels of PDL1 in adenocarcinoma (AD) and squamous cell carcinoma (SC) were significantly higher in patients who died than in patients who did not. There was a trend toward incremental increases in PD1 and PDL1 expression significantly decreasing the risk of relapse and death among AD patients (HR = 0.69; 95% CI = 0.53 ~ 0.91; HR = 0.68; 95% CI = 0.54 ~ 0.84, respectively) and SC patients (HR = 0.53; 95% CI = 0.32 ~ 0.89; HR = 0.78; 95% CI = 0.57 ~ 1.00 respectively), as early-stage patients in this study were more likely to have high expression of both PD1 and PDL1 than late-stage patients (P-trend < 0.05). In contrast, late-stage SC patients expressing one or more of the genes at a high level had a significantly elevated risk of relapse (HR = 1.51; 95% CI = 1.07 ~ 2.11) and death (HR = 1.41; 95% CI = 1.08 ~ 1.84). This result was consistent with the validation data set.ConclusionThese findings indicate that high expression of PD1 and PDL1 is associated with superior outcome in early-stage lung cancer but an adverse outcome in late-stage lung cancer. The expression levels of PD1 and PDL1 individually or jointly are potential prognostic factors for predicting patient outcomes in lung cancer.

A highly specific aptamer probe targeting PD-L1 in tumor tissue sections: Mutation favors specificity

Although DNA aptamers can show comparable affinity to antibodies and have the advantage of having high batch-to-batch consistency, they often suffer from unsatisfied specificity for complex samples. The limited library size used for aptamer in vitro isolation (SELEX) has been recognized as one of the major reasons. Programmed cell death-ligand 1 (PD-L1) is both a key protein in cancer diagnostics and also immunotherapy. We report here a DNA aptamer that highly specifically binds PD-L1 expressed on the surface of various cancer cells and multiple types of tissue sections. The aptamers were selected from a DNA library containing a type II restriction endonuclease Alu I recognition site in the middle of the 40-nt random sequences, against recombinant PD-L1 rather than the whole cell or tissue section. The library enrichment was achieved by Alu I mediated-SELEX, named as REase-SELEX, in which Alu I cut off the non-binders at the recognition site and, more importantly, induced library mutations to substantially increase the library diversity. 8–60, a representative aptamer with high affinity (KD = 1.4 nM determined by SPR) successfully detected four types of cancer cells with PD-L1 expression levels from low to high by flow cytometry, normal human tonsil (gold standard for PD-L1 antibody evaluation), clinical non-small cell lung cancer (high PD-L1 expression level), and malignant melanoma (low PD-L1 expression level) tissue sections by fluorescence microscopy imaging, showing unprecedented high specificity. The results demonstrate that 8–60 is an advanced probe for PD-L1 cancer diagnostics and mutations in SELEX greatly favor aptamer specificity.

Expression of PD-L1 in Relation to Intrinsic Molecular Subtypes of Breast Cancer in Hainan Free Trade Port, China

Background: Intrinsic molecular subtype and histological grade are closely related to clinical prognosis in breast cancer. However, their relationship with Programmed Cell Death-Ligand 1 (PD-L1) expression is not very clear, particularly for Hainan Aboriginal patients. Herein, this research aims to reveal the relationship between PD-L1 expression and intrinsic molecular subtypes of breast cancer. Methods: 225 breast tumor samples from female patients were analyzed for PD-L1 expression using the Immunohistochemistry (IHC) method. The PDL1 expression level was detected by IHC and the relationship between the expression and clinical parameters was analyzed statistically. Results: Positive staining of PD-L1 was mainly found in the plasma membrane. In all cases, the positive rate was 12.0% (27/225). The PD-L1 expression level was significantly reduced in Luminal A subtype (the corrected ratio OR=0.15, p=0.04) whereas increased in HER2-positive subtype (OR=4.2, p=0.01). PD-L1 was significantly related to HER2-positive subtype (p&lt;0.05) and histological grade 3 (p&lt;0.05). There was statistically significant association between PD-L1 expression and metastasis (p=0.046), but not with the patient’s age, the tumor stage and menstruation (p&gt;0.05). Moreover, there was a significant difference in the frequency of intrinsic subtypes between patients with positive and negative PD-L1 expression (p&lt;0.001) among patients with metastasis. Conclusions: PD-L1 expression in breast cancer was positively correlated with HER2-positive subtype, higher pathological grade and metastasis of breast cancer, while negatively correlated with Luminal A in female patients in Hainan, China. PD-L1 may be a new independent marker to predict the prognostic factor in HER2-positive subtype breast cancer.

Study of Gene Expression of Programmed Cell Death Ligand 1 (PD-L1) in Breast Cancer Patients

Introduction: Breast cancer is the most frequently occurring cancer among females and the second most common cancer overall. Programmed Cell Death Ligand 1 (PD-L1) plays an important role in blocking ‘cancer-immunity cycle’ and is considered as a major inhibitory pathway. The aim of the present study was to clarify the alterations of expression of PD-L1 in peripheral blood mononuclear cytes (PBMCs) of female breast cancer patients and analyze its association with clinico-pathological criteria as well as therapeutic response. Materials and Methods: The study was conducted on 45 female breast cancer patients and 45 female controls. Blood samples were collected followed by PBMCs isolation, total RNA extraction, reverse transcription and finally, quantitative polymerase chain reaction (qPCR) using SYBR Green DNA binding dye. Expression levels of PD-L1 were calculated and then compared with clinicopathological parameters of the patients in addition to initial therapeutic response. Results: A significant difference was detected for PD-L1 expression levels in breast cancer patients compared to controls. A significant association with age, metastatic breast cancer, estrogen receptor (ER) negative status as well as high concentrations of cancer antigen 15-3 (CA15-3) was detected. On the other hand, no significant association was recognized with tumor size, lymph nodal status, histopathological type, grade, progesterone receptor (PR) status, human epidermal growth factor receptor 2 (HER-2) status, triple negative, among de novo and recurrent metastatic patients and for the number of metastatic sites as well as the therapeutic response. Conclusions: This study paves the way of the use of PD-L1 as a noninvasive prognostic and diagnostic biomarker for poor prognosis of breast cancer.

Effects of transarterial chemoembolization on the immunological function of patients with hepatocellular carcinoma.

The present study aimed to investigate the effects of transarterial chemoembolization (TACE) on the immune function of patients with hepatocellular carcinoma (HCC). A total of 114 patients with HCC were selected and their peripheral blood was collected before and 1 month after TACE treatment. Flow cytometry and reverse transcription-quantitative PCR were performed to analyze the changes in immune function in patients before and after treatment. Kaplan-Meier curves were plotted for survival analysis. The programmed cell death ligand 1 (PD-L1) and programmed cell death protein 1 (PD1) expression before TACE treatment were significantly higher in patients with poor TACE response compared with those patients with well response. Higher PD-L1 mRNA expression in the peripheral blood mononuclear cells after TACE predicted a superior prognosis. After TACE treatment, the proportion of CD4+/CD8+ cells were decreased while the expression levels of programmed cell death protein 1 (PD1) were significantly increased. To conclude, TACE could reduce the proportion of CD4+/CD8+ cells and improve the mRNA expression levels of PD1 in patients with HCC. The expression levels of PD1 and PD-L1 were closely related to the therapeutic effect of TACE and the prognosis of patients with HCC. TACE combined with immunotherapy may have potential clinical value for patients with HCC.

A narrative review of current and potential prognostic biomarkers for immunotherapy in small-cell lung cancer.

Small-cell lung cancer (SCLC) is a highly invasive and rapidly proliferating pathologic subtype that accounts for 13–15% of all lung cancer cases. Recently in extensive-stage SCLC, treatments that combine immunotherapy and chemotherapy showed increased efficacy compared to chemotherapy alone in several trials. However, the combination of immunotherapy and conventional chemotherapy regimens was introduced only recently for extensive-stage SCLC, with relatively little real-world data. The demand for reliable biomarkers that can predict the efficacy of immunotherapy in SCLC is high. Several studies evaluated various parameters including programmed cell death ligand-1 (PD-L1) expression, tumor mutation burden (TMB), gene expression profiling, autoantibody, and blood cytokines for predictive value for response to immunotherapy in SCLC. Despite some observed correlations, there is a lack of concrete support for the use of PD-L1 expression levels for readily available biomarker. High TMB in combination with smoking history is predictive of a better response to immunotherapy, but validation of cutoffs and testing methods is necessary before it can be widely applied in clinical settings. Other candidate biomarkers such as immune cell distribution among tumor microenvironment, and systemic inflammatory markers can also be evaluated, after an accumulation of real-life data from SCLC patients under immunotherapy.

Immune Checkpoint Inhibitors in Urothelial Carcinoma: Recommendations for Practical Approaches to PD-L1 and Other Potential Predictive Biomarker Testing

Simple SummaryThe predominant histologic type of bladder cancer is urothelial carcinoma (UC). Programmed cell death-ligand 1 (PD-L1) expression levels in UC tumors help clinicians determine which patients are more likely to respond to immuno-oncology (IO) therapies; as such, the harmonization of PD-L1 testing in evaluating patients is increasingly important. A series of international workshops, involving renowned pathologists and oncologists, were held to develop best practice approaches to PD-L1 testing in UC. It was agreed that robust control of analytical standards is required to obtain quality PD-L1 results and that interpretation and reporting of PD-L1 require clear inter-clinician communication. Recommendations for the best practices for PD-L1 testing in UC are provided. A PD-L1 test request form for pathology laboratories was also developed and included here, encouraging communication between clinicians and pathologists, and ensuring fast and high-quality test results. Novel biomarkers being evaluated for immuno-oncology agents in UC are also briefly discussed.Immuno-oncology (IO) agents (anti–programmed cell death 1 (PD-1) and anti–programmed cell death-ligand 1 (PD-L1)) are approved as first- and second-line treatments for metastatic UC. PD-L1 expression levels in UC tumors help clinicians determine which patients are more likely to respond to IO therapies. Assays for approved IO agents use different antibodies, immunohistochemical protocols, cutoffs (defining “high” vs. “low” PD-L1 expression), and scoring algorithms. The robust control of pre-analytical and analytical standards is needed to obtain high-quality PD-L1 results. To better understand the status and perspectives of biomarker-guided patient selection for anti–PD-1 and anti–PD-L1 agents in UC, three workshops were held from December 2018 to December 2019 in Italy, Malaysia, and Spain. The primary goal was to develop recommendations for best practice approaches to PD-L1 testing in UC. Recommendations pertaining to the interpretation and reporting of the results of PD-L1 assays from experienced pathologists and oncologists from around the globe are included. A test request form for pathology laboratories was developed as a critical first step for oncologists/urologists to encourage communication between clinicians and pathologists, ensuring fast and high-quality test results. In this era of personalized medicine, we briefly discuss novel biomarkers being evaluated for IO agents in UC.

PD-L1 Expression and Outcome in Patients with Metastatic Non-Small Cell Lung Cancer and EGFR Mutations Receiving EGFR-TKI as Frontline Treatment.

BackgroundEpidermal growth factor receptor (EGFR) mutations are most common in Eastern Asia, and frequencies of 30–50% have been reported. EGFR-tyrosine kinase inhibitors (TKIs) are recommended as first-line therapeutic options for non-small cell lung cancer (NSCLC) with sensitizing EGFR mutations. Several immune checkpoint inhibitors have been successful in improving the outcomes of advanced lung cancer. The expression of programmed cell death-ligand 1 (PD-L1) on tumor cells plays an important role in predicting the efficacy of programmed cell death protein 1/PD-L1 inhibitors. The role of PD-L1 expression in tumors with EGFR mutation and its influence on clinical outcomes remain controversial.MethodsPatients with newly diagnosed metastatic NSCLC with sensitizing EGFR mutations who received the standard treatment, ie, EGFR-TKIs for mutant adenocarcinoma as the first-line treatment, were enrolled in this retrospective study. EGFR mutations and PD-L1 expression levels were detected by Cobas RT-PCR and Dako 22C3 immunohistochemistry staining, respectively.ResultsFrom January 2011 to February 2019, 114 patients were enrolled. The average age was 62 years (range 34–92), and 45 (39.5%) patients were male. Among these patients, EGFR mutation analysis revealed exon 19 in-frame deletion in 55 (48.2%) patients, exon 21 L858R in 53 (46.5%) patients, and uncommon mutations in 6 (5.3%) patients. Among these patients with EGFR mutations, PD-L1 expression levels by tumor proportion score (TPS) were <1% in 54 (46.9%) patients, 1–49% in 50 (44.2%) patients, and ≥50% in 10 (8.8%) patients. All patients received EGFR-TKIs as first-line treatment, and in the Kaplan-Meier analysis, progression-free survival was not significantly different among groups with different PD-L1 expression status.ConclusionFor patients with metastatic NSCLC and EGFR mutations, PD-L1 expression is not uncommon, but no significant influence on clinical outcomes was observed in patients receiving standard initial treatment.

Co-expression of CMTM6 and PD-L1: a novel prognostic indicator of gastric cancer

BackgroundCKLF Like MARVEL Transmembrane Domain Containing 6 (CMTM6) is involved in the epigenetic regulation of genes and tumorigenesis. Programmed cell death ligand 1 (PD-L1) is closely related to the prognosis of some human cancers. CMTM6 is a key regulator of PD-L1 in many cancers. The purpose of this study was to investigate the expressions of these proteins in gastric cancer and the correlations with clinicopathological features and survival.MethodsThe expression levels of CMTM6 and PD-L1 were examined in 185 gastric cancer specimens using immunohistochemistry, quantitative real-time PCR and Western blot. Immunofluorescence was used to examine the localizations of CMTM6 and PD-L1. Chi-square test was used to analyze the relationship between CMTM6 and PD-L1 expressions and clinicopathological characteristics. Kaplan–Meier method and log-rank test were used to analyze the survival data of patients.ResultsThe positive expression rates of CMTM6 and PD-L1 in gastric cancers were 78.38% (145/185) and 75.68% (140/185), respectively. CMTM6 and PD-L1 were both mainly expressed in the cell membrane and nucleus of gastric cancer tumor cells. High expression of CMTM6 and PD-L1 was correlated with Borrmann type (P < 0.001), N stage (P = 0.002), peritoneal metastasis (P = 0.007) and TNM stage (P = 0.038). CMTM6 and PD-L1 expression in gastric cancer tissues showed a positive correlation (Pearson’s coefficient test, r = 0.260; P < 0.001). CMTM6 may positively regulate PD-L1 expression. High expression of CMTM6 was correlated with poor prognosis of gastric cancer patients (HR = 1.668; 95% CI = 1.032–2.695; P = 0.037). High expression of both CMTM6 and PD-L1 may be an independent factor for overall survival (HR = 1.554; 95% CI = 1.011–2.389; P = 0.044).ConclusionThe combined detection of CMTM6 and PD-L1 may be used as an indicator for judging the prognosis of gastric cancer patients.

Simultaneous high PD-L1 and low VEGFR2 expression is associated with better overall survival in rectal cancer.

BackgroundThe aim of the present study was to analyze the association of programmed cell death-ligand 1 (PD-L1) and vascular endothelial growth factor receptor 2 (VEGFR2) expression levels with clinicopathological characteristics and survival to provide a treatment strategy for rectal cancer.MethodsImmunohistochemical staining of VEGFR2 and PD-L1 was carried out, and the association of PD-L1 and VEGFR2 expression levels with clinicopathological characteristics and survival were investigated in 77 pair-matched rectal cancer patients.ResultsPD-L1 and VEGFR2 expression levels in surgical tumor tissues were higher than those in paired adjacent normal tissues, respectively (both P<0.05). The results of the 5-year overall survival (OS) analysis showed that patients with low VEGFR2 expression (66.7% vs. 43.5%, P=0.042) and high tumor PD-L1 expression (63.9% vs. 26.1%, P=0.001) in tumor tissues demonstrated significantly better OS. Patients with high TNM stage had poorer OS [hazard ratio (HR): 2.093, 95% confidence interval (CI): 1.027–4.087, P=0.030]. Similar results of poorer OS could be seen in patients with low tumor PD-L1 expression (HR: 3.365, 95% CI:1.747–6.481, P=0.005), as well as patients with high tumor VEGFR2 expression (HR: 0.418, 95% CI: 0.232–0.993, P=0.048).ConclusionsThe results indicated that tumor PD-L1 and VEGFR2 expression levels were associated with OS, and the combination of tumor PD-L1 and VEGFR2 levels might be an independent prognostic factor in rectal cancer.

Predictive values of genomic variation, tumor mutational burden, and PD-L1 expression in advanced lung squamous cell carcinoma treated with immunotherapy.

BackgroundImmune checkpoint inhibitors (ICIs) prolong overall survival (OS) in patients with advanced lung squamous cell carcinoma (LUSC). However, predictive and prognostic factors related to ICIs in LUSC remain elusive. This study aimed to identify predictors that are related to better clinical benefit and outcomes in LUSC patients treated with immunotherapy.MethodsCapture-based targeted sequencing was performed in 64 patients with advanced LUSC who underwent immunotherapy. Tumor mutational burden (TMB) was defined as the sum of nonsynonymous single nucleotide and indel variants. Programmed cell death ligand-1 (PD-L1) expression was evaluated by immunohistochemical analysis. Clinicopathological characteristics including age, sex, performance status, smoking history, body mass index (BMI), blood fat, brain metastases, liver metastases, previous thoracic radiotherapy, and treatment lines were analyzed.ResultsThe most commonly mutated genes included TP53, CDKN2A, KEAP1, CREBBP, KRAS, BIM, AMER1, and APC. Copy number variations most frequently occurred in AR, SOX2, PIK3CA, EGFR, RICTOR, FGFR1, and ZNF703. The median and mean TMB was 9.35 and 10.62 mutations per megabase, respectively. Positive PD-L1 expression was detected in 29.7% patients. Patients with a history of heavy smoking (≥ 40 pack-years) were more likely to have positive PD-L1 expression (35% vs. 16.7%, P=0.04) and higher TMB (11.1 vs. 9.8 mut/Mb, P=0.04). Gene alterations had no impact on PD-L1 expression or TMB level. The median progression-free survival (PFS) was 6.7 months and median OS was 13.7 months. Higher TMB was independently associated with longer PFS (P=0.01) and OS (P=0.02), and this correlation was more pronounced in patients treated with ICIs as a single agent (P=0.0001). Higher TMB was also associated with better disease control rate (DCR) (P=0.02). Compared with wild-type, patients with KRAS mutation and EGFR amplification had higher objective response rates (ORR, P=0.01).ConclusionsThe predictive value of TMB is more significant in LUSC patients receiving ICI as a single agent than as a combination therapy. The combination of Eastern Cooperative Oncology Group performance status (ECOG-PS), smoking status, TMB, PD-L1, and genomic variation might be helpful for personalized immunotherapy decisions in clinical practice for advanced LUSC.

KPNB1-mediated nuclear translocation of PD-L1 promotes non-small cell lung cancer cell proliferation via the Gas6/MerTK signaling pathway

In addition to the role of programmed cell death ligand 1 (PD-L1) in facilitating tumour cells escape from immune surveillance, it is considered as a crucial effector in transducing intrinsic signals to promote tumour development. Our previous study has pointed out that PD-L1 promotes non-small cell lung cancer (NSCLC) cell proliferation, but the mechanism remains elusive. Here we first demonstrated that PD-L1 expression levels were positively correlated with p-MerTK levels in patient samples and NSCLC cell lines. In addition, PD-L1 knockdown led to the reduced phosphorylation level of MerTK in vitro. We next showed that PD-L1 regulated NSCLC cell proliferation via Gas6/MerTK signaling pathway in vitro and in vivo. To investigate the underlying mechanism, we unexpectedly found that PD-L1 translocated into the nucleus of cancer cells which was facilitated through the binding of Karyopherin β1 (KPNB1). Nuclear PD-L1 (nPD-L1), coupled with transcription factor Sp1, regulated the synthesis of Gas6 mRNA and promoted Gas6 secretion to activate MerTK signaling pathway. Taken together, our results shed light on the novel role of nPD-L1 in NSCLC cell proliferation and reveal a new molecular mechanism underlying nPD-L1-mediated Gas6/MerTK signaling activation. All above findings provide the possible combinational implications for PD-L1 targeted immunotherapy in the clinic.

Water extract of sporoderm-broken spores of Ganoderma lucidum enhanced pd-l1 antibody efficiency through downregulation and relieved complications of pd-l1 monoclonal antibody

PurposeOsteosarcoma is a malignant musculoskeletal tumor with early metastasis and a poor prognosis, especially in adolescents. Ganoderma lucidum (Leyss. Ex Fr.) Karst (G. lucidum), a traditional East Asian medicine, has been reported to play a critical role in antitumor and immunomodulatory activity. The aim of this study was to investigate the effects and molecular mechanisms of water extract of sporoderm-broken spores of G. lucidum (BSGWE) on osteosarcoma PD-L1 (programmed cell death-ligand 1) transcriptional regulation, efficacy enhancement, and side effect remission. MethodsThe antitumor effects on cell proliferation of BSGWE in osteosarcoma cells were detected by apoptosis flow cytometry, and the migration ability of HOS and K7M2 cells were evaluated by cell scratch assay. Potential signaling regulation of PD-L1 was detected by western blotting. To confirm the signaling pathway of BSGWE-related PD-L1 downregulation, a pho-STAT3 turnover experiment was carried out. Colivelin was administered as a pho-STAT3 activator to rescue the BSGWE-induced PD-L1 inhibition. To further study in vivo signaling, in a Balb/c osteosarcoma allograft model, tumor volume was measured using an in vivo bioluminescence imaging system. The body weight curve and tumor volume curve were analyzed to reveal the remission effects of BSGWE on PD-L1 antibody-related body weight loss and its immunomodulatory effects on the osteosarcoma and spleen. The PD-L1 expression level and expression of related transcription-factor pho-STAT3 in tumor cells and spleens were assessed by IHC analysis. ResultsBSGWE suppressed the proliferation and migration of osteosarcoma cells in vitro via induction of apoptosis. In addition, BSGWE downregulated PD-L1 expression and related STAT3 (signal transducers and activators of transcription) phosphorylation levels in a dose-dependent manner. Western blotting and qRT-PCR assay revealed that BSGWE downregulated PD-L1 expression by inhibiting STAT3 phosphorylation. A turnover experiment showed that colivelin administration could rescue PD-L1 inhibition via pho-STAT3 activation. BSGWE not only downregulated PD-L1 expression via the STAT3 pathway in an allograft Balb/c mouse model, but also relieved complications including weight loss and spleen atrophy in a mouse monoclonal antibody therapy model on the basis of its traditional advantages in immune enhancement. ConclusionBSGWE downregulated PD-L1 expression via pho-STAT3 inhibition of protein and RNA levels. BSGWE enhanced PD-L1 antibody efficacy via phosphorylated STAT3 downregulation in vitro and in vivo. BSGWE also relieved complications of weight loss and spleen atrophy in a murine allograft osteosarcoma immune checkpoint blockade therapy model.

Protein tyrosine phosphatase receptor type delta (PTPRD) suppresses the expression of PD-L1 in human hepatocellular carcinoma by down-regulating STAT3.

BackgroundProtein tyrosine phosphatase receptor type delta (PTPRD) is a tumor suppressor that is often inactivated in hepatocellular carcinoma (HCC). However, the mechanisms of how PTPRD inhibits HCC are not well understood. Programmed cell death ligand 1 (PD-L1), an immune checkpoint, plays a seminal role in the regulation of carcinogenesis of HCC. The sustained activation of STAT3 is closely related to PTPRD deletion and PD-L1 overexpression; however, whether there is a relationship between PTPRD and PD-L1 expression in HCC has not been investigated. This study aims to investigate the relationship between PTPRD and PD-L1 in HCC samples and illuminate potential new molecular mechanisms of PTPRD effects on PD-L1 in HepG2 cells.MethodsWe collected 16 pairs of tumorous tissues and adjacent normal tissues from HCC patients. The mRNA and protein expression levels of PTPRD and PD-L1 in the HCC tissues were detected by RT-PCR and Western blot analysis. Next, Spearman’s correlation analysis was performed to evaluate the relationship between PTPRD and PD-L1. Then, we transfected the overexpressed or knocked-down PTPRD genes into the HepG2 cell line, and the effects of PTPRD on PD-L1 in HCC cells were evaluated. The activity from the STAT3 and p-STAT3 in the HepG2 cells transfected with PTPRD gene overexpression and knockdown was determined by Western blotting tests.ResultsThe expression of PTPRD was significantly down-regulated in the HCC tissues compared with the adjacent control tissues; however, PD-L1 was significantly higher in the HCC tissues. There was a negative correlation between PTPRD and PD-L1 expression in the HCC tissues. PTPRD over-expression significantly inhibited PD-L1 expression; meanwhile, PTPRD depletion promoted PD-L1 expression in the HepG2 cells. Furthermore, PTPRD over-expression significantly inhibited the expression of STAT3 and p-STAT3, while PTPRD depletion promoted these cytokines. Our studies revealed that PTPRD repressed PD-L1 expression in the HepG2 cells, which might occur via the STAT3 pathway.ConclusionsThe results from our study show that PTPRD and PD-L1 are negatively correlated in HCC tissues. PTPRD suppresses PD-L1 expression in HepG2 cells by down-regulating STAT3. These findings are expected to become a new target for the immunotherapy of HCC.

The Impacts of Different Types of Radiation on the CRT and PDL1 Expression in Tumor Cells Under Normoxia and Hypoxia.

IntroductionHypoxia is a hallmark of cancer that may contribute to an immunosuppressive microenvironment and promote radioresistance. High linear energy transfer (LET) radiation is considered to be able to overcome the negative effects of hypoxia. However, the anti-tumorigenic effects induced by low or high LET radiation have not been fully elucidated. This study aimed to compare the effects of different types of radiation on the immune response, particularly the impact on calreticulin (CRT), and programmed cell death ligand 1 (PDL1) expression.MethodsFour human tumor cell lines were investigated in this study. Cells in normoxic and hypoxic groups were irradiated with 4Gy (physical dose) photon, proton, and carbon-ion radiation, respectively. The expression of CRT and PDL1 was detected 48 h after irradiation, and the median fluorescence intensities (MFIs) were compared by flow cytometry. Meanwhile, the radiosensitivity of tumor cells in each group was also compared by colony formation assays and flow cytometry.ResultsAll types of radiation could significantly inhibit the colony formation of tumor cells under normoxia. However, the efficacy of photon and proton radiation was impaired under hypoxia. Carbon-ion radiation could still inhibit colony formation. The percentage of viable cells after irradiation was higher under hypoxia compared with those under normoxia. The CRT expression under normoxia was significantly increased after radiation. Carbon-ion radiation enhanced CRT expression compared to photon and proton radiation. Conversely, under hypoxia, the CRT expression level was significantly upregulated at baseline (0Gy). Radiation could not increase the expression further. PDL1 expression was also significantly increased by radiation under normoxia in all cell lines except the Ln18 cell line. Carbon-ion radiation induced the most significant increase. Under hypoxia, the PDL1 expression level was also upregulated at baseline and radiation could not increase expression further.ConclusionTumor cells were resistant to photon and proton but sensitive to carbon-ion radiation under hypoxia. Carbon-ion radiation could induce the highest CRT and PDL1 expression under normoxia. However, under hypoxia, radiation could not further enhance the high baseline expression of CRT and PDL1.

Prognostic impacts of tumoral expression and serum levels of PD-L1 and CTLA-4 in colorectal cancer patients.

Programmed cell death ligand-1 (PD-L1) and cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) play a pivotal role in cancer immunotherapy. Each of these molecules has a membrane-bound receptor form (mPD-L1/mCTLA-4) and a soluble form (sPD-L1/sCTLA-4). However, these prognostic impacts in colorectal cancer (CRC) remain unclear. We immunohistochemically scored tumoral mPD-L1/mCTLA-4 expression and quantified preoperative circulating sPD-L1/sCTLA-4 levels using matched serum specimens from 131 patients with pStage I-III CRC. We also examined the association between these statuses and tumor infiltrating lymphocytes (TILs) in these patients. Elevated levels of mPD-L1, mCTLA-4, sPD-L1 and sCTLA-4 were significantly correlated with poor overall survival (OS) and disease-free survival (DFS). Co-high expression of tumoral mPD-L1 and mCTLA-4 or co-elevated levels of serum sPD-L1 and sCTLA-4 were strongly correlated with poor OS and DFS. Multivariate analysis revealed that both statuses were negative independent prognostic factors for OS [hazard ratio (HR) 3.86, 95% confidence interval (95% CI) 1.71-8.51, p = 0.001; HR 5.72, 95% CI 1.87-14.54, p = 0.004, respectively] and DFS (HR 2.53, 95% CI 1.23-4.95, p = 0.01; HR 6.88, 95% CI 2.42-17.13, p = 0.0008, respectively). Although low expression of tumoral mCTLA-4 was significantly correlated with increased CD8(+) TILs, there was no correlation in any other combination. We verified the prognostic impacts of mPD-L1, mCTLA-4, sPD-L1 and sCTLA-4 in pStage I-III CRC patients. Dual evaluation of immune checkpoint molecules in primary tissues or preoperative serum could identify a patient population with poor prognosis in these patients.