Expression Of Programmed Cell Death Protein Research Articles

Evaluation of PD-1 and interleukin-10-receptor expression by T lymphocytes in malignant and benign pleural effusions

PD-1 (programmed cell death protein-1)/PD-L1 (programmed cell death ligand 1) as well as IL-10 (interleukin-10)/IL-10R (interleukin-10 receptor) interactions play a major role in tumor immune evasion in various malignancies. Several studies investigated the expression of PD-1 on T lymphocytes in pleural effusions (PE) in patients with malignant diseases. However, results in malignant pleural effusions (MPE) compared to benign PE (BPE) are underreported. In this prospective study, 51 patients (median age 66 years, IQR 54–78, 47% male) with PE of malignant or benign origin at the Medical University of Vienna between March 2021 and November 2022 were enrolled and divided into three groups according to the cytological results (group 1: MPE [n = 24, 47%]; group 2: BPE in malignant disease [n = 22, 43%]; group 3: BPE in benign disease [n = 5, 10%]). In the cytological samples, T cells were analyzed for the expression of PD-1 and IL-10R via flow cytometry. In MPE, the proportion of PD-1+ T lymphocytes on CD4+ cells was significantly lower than in BPE (40.1 vs. 56.3 in group 1 vs. 3, p = 0.019). Moreover, a significantly lower expression of PD-1+ IL-10R+ CD8+ (9.6 vs. 35.2 in group 1 vs. 2, p = 0.016; 9.6 vs. 25.0 in group 1 vs. 3, p = 0.032) and a significantly higher expression of PD-1-IL-10R-CD8+ T lymphocytes (43.7 vs. 14.0 in group1 vs. 2, p = 0.045; 43.7 vs. 23.3 in group 1 vs. 3, p = 0.032) were observed in MPE when compared to BPE. The frequency of T cells expressing PD-1 and IL-10R on CD8+ T cells is significantly lower in MPE compared to BPE regardless of the underlying disease indicating a different microenvironment in PE driven by the presence of tumor cells. Our observation spotlights the possible involvement of PD-1 and IL-10R in MPE.

Evaluation of the level expression of the Russian clone of PD-L1 antibodies and comparison with validated clones from other manufacturers on stomach cancer material

The study of immunotherapeutic markers is one of the most popular and promising areas in oncology. One of the most studied targets of immunotherapy is the ligand of the programmed cell death protein 1 (PD-L1). All diagnostic kits for determining PD-L1 expression in tumors are of foreign origin. To ensure the technological sovereignty of the Russian Federation in the field of medical technologies, it is necessary to conduct research with a domestic clone of PD-L1 antibodies and compare the results with already validated analogues. The aim of the work was to evaluate the expression of a domestic clone of antibodies to PD-L1 (PBM-1A4), determine its relationship with the clinical and morphological parameters of gastric cancer and compare the expression of various PD-L1 clones in gastric cancer (SP142, SP263, 22C3 and PBM-1A4). The study was performed on samples of gastric cancer surgical material from 131 patients who had not received chemotherapy, radiation or immunotherapy before surgery. Results: PD-L1 expression detected by the PBM-1A4 antibody clone is present in 46.2% of gastric cancer samples. Among PD-L1(PBM-1A4)-positive tumors, neoplasms of the second macroscopic type according to R. Bormann and tubular adenocarcinomas significantly predominate. The SP142 clone shows the greatest consistency with PBM 1A4 expression (significant consistency, Cohen's kappa is 0.67335). Conclusion: This antibody clone undoubtedly represents an extremely promising development by Russian scientists, which makes it possible to make the molecular diagnosis of malignant neoplasms more accessible to Russian patients.

Comparison of tissue biomarkers between non-schistosoma and schistosoma-associated urothelial carcinoma

BackgroundHigh-grade urothelial carcinoma either non-Schistosoma (NS-UBC) or Schistosoma (S-UBC)-associated is the tenth cause of death worldwide and represents a serious therapeutic problem. AimEvaluation of the immmunohistochemical expression of tumor necrosis factor-alpha (TNFα), epidermal growth factor receptor (EGFR), programmed cell death protein-1 (PDL1), estrogen receptor-alpha (ERα) and UroplakinIII, in the high-grade in NS-UBC and S-UBC as potential prognostic and therapeutic targets analyzed through estimation of area percentage, optical density and international pathological scoring system for each marker. Material and methodsSixty high grade urothelial carcinoma cases were enrolled in the study (30 cases of NS-UBC and 30 cases of S-UBC). The cases were immunohistochemically-assessed for TNFα, EGFR, PDL1, ERα and Uroplakin III expression. In S-UBC, parasite load was also evaluated for correlation with the immunohistochemical markers’ expression in S-UBC. ResultsThe area percentage of immune-expression of TNFα and EGFR was higher in S-UBC compared to NS-UBC. On the other hand, the NS-UBC displayed statistically-higher expression of PDL1 and uroplakinIII (p-value <0.001). ERα revealed higher, yet, non-significant expressions in S-UBC compared to NS-UBC (p-value =0.459). PDL1 expression showed the most superior record regarding area percentage (64.6± 34.5). Regarding optical density, TNF-α showed the highest transmittance expression (2.4 ± 0.9). EGFR positively correlated with PDL1 in S-UBC (r= 0.578, p-value =0.001) whereas in NS-UBC, TNFα and PDL1 (r=0.382, p-value=0.037) had positive correlation. Schistosoma eggs in tissues oppose uroplakin III expression and trigger immunomodulation via PDL1. ConclusionDue to lower UroplakinIII expression, S-UBC is supposed to have a poorer prognosis. Hormonal therapy is not hypothesized due to a very minimal ERα expression in both NS-UBC and S-UBC. Regarding immunotherapy, anti-TNF-α is suggested for S-UBC whilst in NS-UBC, blockading PDL1 might be useful. Targeted EGFR therapy seems to carry emphasized outcomes in S-UBC. Correlations encourage combined immune therapy in NS-UBC; nevertheless, in S-UBC, combined anti-EGFR and PDL1 seem to be of benefit.

Abstract LB445: USP24 suppresses T cell anti-tumor activity by enhancing the stability of the PD-1 protein

Abstract Persistent programmed cell death-1 (PD-1)/PD-L1 inhibitory signaling disrupts T cell cytotoxic function, leading to T cell exhaustion—a phenomenon strongly associated with advanced cancer progression and immunotherapy failure. Deciphering the mechanisms behind dysregulated PD-1 expression and reactivating tumor-infiltrating lymphocytes (TILs) in the tumor microenvironment (TME) is crucial. Our previous research established that tumor-associated macrophage-derived IL-6 promotes STAT3-dependent PD-1 transcriptional activity and immunotherapy resistance. The current study further explores whether IL-6 abundance in the TME contributes to PD-1 protein stability. Results indicate that IL-6 extended PD-1 protein half-life in T cells, suggesting its role in modulating PD-1 protein stability. Furthermore, analysis of the GEO database showed a positive correlation between the expression of ubiquitin-specific-processing protease (USP) family enzymes and PD-1 in non-responding patients receiving anti-PD-1 therapy. Knockdown experiments revealed that USP24 strongly downregulated PD-1 protein expression and stability. USP24 depletion reversed IL-6-induced PD-1 expression and stability, with USP24 colocalizing with PD-1 at the plasma membrane upon IL-6 stimulation. Immunoprecipitation-Western blot assays confirmed that USP24 directly interacted with PD-1 and countered E3 ligase c-Cbl-mediated ubiquitination. Depleting USP24 suppressed PD-1-mediated immunosuppression both in vitro and in vivo. In lung-specific EGFRL858R/USP24C1698A functional knockout mice, tumor progression was slower, and exhausted tumor-infiltrating PD-1+ TIM-3+ CD8+ T cells reduced compared to EGFRL858R mice. Inhibiting PD-1 stability with an IL-6 neutralizing antibody or the novel inhibitor USP24-i-101 decreased tumor volume and increased activated cytotoxic T cell infiltration in vivo. Moreover, USP24-i-101 enhanced therapeutic effects in combination with anti-CTLA4 immunotherapy. Clinically, our in-house cohort revealed elevated USP24 expression in tumor-infiltrating lymphocytes or peripheral T cells, correlating with worse clinical outcomes and unfavorable responses to immunotherapy in lung cancer patients. This study uncovers USP24 as a novel PD-1 regulator, deubiquitinating PD-1 to enhance protein stability and suppress T cell function. In conclusion, USP24 emerges as a potential target for enhancing anti-tumor immunity and as a biomarker predicting clinical responses to immunotherapy in lung cancer. Citation Format: Hung-Chia Hsieh, Jan-Jong Hung, Yi-Ching Wang. USP24 suppresses T cell anti-tumor activity by enhancing the stability of the PD-1 protein [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB445.

A Study on the Immunoregulatory Role of the PD1 Pathway in Juvenile Idiopathic Arthritis.

To investigate the immunoregulatory role of the Programmed-cell-Death-protein-1 (PD1) pathway, an inhibitory immune checkpoint, in Juvenile Idiopathic Arthritis (JIA). The PD1 expression on CD4+ and CD8+ T-cells was determined by flow cytometry and the PD1 soluble form (sPD1) levels by ELISA, in peripheral blood (PB)/serum and synovial fluid (SF) samples of JIA patients and healthy controls (HCs). We searched for any association in-between the biomarkers and with JIA activity. 101 Caucasian patients (69 female), aged 12 (8-15) years, and 20 HCs participated in this study. The PB PD1 expression on T-cells was higher in: a. JIA patients vs HCs (CD4: 1.24% vs 0.32%, p=0.007, CD8: 1.6% vs 0.4%, p=0.002). b. active vs inactive JIA (CD4: 1.44% vs 0.87%, p=0.072, CD8: 2.1% vs 0.93%, p=0.005). The SF PD1 expression on T-cells correlated strongly and positively with the disease activity (CD4: ρ=0.55, p=0.022, CD8: ρ=0.555, p=0.026). The SF PD1 expression on CD8 T-cells was higher in patients on-treatment vs those off-treatment (21.3% vs 5.83% p=0.004). The sPD1 levels were higher in the SF vs the serum (801pg/ml vs 367.2, p=0.013), without an association with disease activity. These results indicate an up-regulation of the PD1-pathway in JIA, at least quantitatively, especially in active disease. sPD1 is compartmentally produced at the inflamed joints. Further investigation in a larger sample of JIA patients may verify these observations and contribute to unravelling the precise role of the PD1 pathway in the pathogenesis and persistence of the joint inflammation.

Tumor cell-intrinsic PD-1 promotes Merkel cell carcinoma growth by activating downstream mTOR-mitochondrial ROS signaling.

Merkel cell carcinoma (MCC) is a rare and aggressive skin cancer. Inhibitors targeting the programmed cell death 1 (PD-1) immune checkpoint have improved MCC patient outcomes by boosting antitumor T cell immunity. Here, we identify PD-1 as a growth-promoting receptor intrinsic to MCC cells. In human MCC lines and clinical tumors, RT-PCR-based sequencing, immunoblotting, flow cytometry, and immunofluorescence analyses demonstrated PD-1 gene and protein expression by MCC cells. MCC-PD-1 ligation enhanced, and its inhibition or silencing suppressed, in vitro proliferation and in vivo tumor xenograft growth. Consistently, MCC-PD-1 binding to PD-L1 or PD-L2 induced, while antibody-mediated PD-1 blockade inhibited, protumorigenic mTOR signaling, mitochondrial (mt) respiration, and ROS generation. Last, pharmacologic inhibition of mTOR or mtROS reversed MCC-PD-1:PD-L1-dependent proliferation and synergized with PD-1 checkpoint blockade in suppressing tumorigenesis. Our results identify an MCC-PD-1-mTOR-mtROS axis as a tumor growth-accelerating mechanism, the blockade of which might contribute to clinical response in patients with MCC.

Abstract 6636: Metformin suppresses tumor immune evasion through downregulation of PD-L1 expression in cancer cells and PD-1 expression in NK cells and T cells

Abstract Up-regulation of programmed cell death 1 (PD-1) receptor on T cells and its ligand (PD-L1) on cancer cells is reported in various tumor microenvironment, and the interaction between PD-L1 and PD-1 inhibits the cytotoxic activity of NK cells and T cells, allowing cancer cells to evade immune destruction. Extensive studies suggested that metformin, the most widely used first-line drug for treatment of type 2 diabetes, had a potential efficacy of enhancing anti-tumor immune response. However, the detail mechanisms underlying the efficacy are unknown. Here, we showed that metformin decreases AKT-mediated β-catenin S552 phosphorylation and β-catenin transactivation in an AMPK activation-dependent manner, resulting in reduced CD274 transcription in cancer cells. In the cocultures of cancer cells with NK cells or T cells, cancer cells induced PD-1 protein stability and expression in the NK cells and T cells, these PD-1 upregulation was also observed in infiltrated NK cells and T cells in vivo mouse tumors. Metformin reduced the half-life and expression of PD-1 in an AMPK activation-dependent manner in vitro and in vivo. These inhibitory roles of metformin in PD-L1 expression in cancer cells and in cancer cell-induced PD-1 expression in NK cells and T cells led to ameliorated the cancer cell-reduced cytotoxic activity of NK cells and T cells and inhibited tumor growth in vivo models. These findings suggest that metformin may act as both PD-L1 and PD-1 blockades within tumor microenvironment, providing a mechanistic insight for the efficacy of metformin to improve immunotherapy in human cancer. Citation Format: Su Hwan Park, Jong-Ho Lee. Metformin suppresses tumor immune evasion through downregulation of PD-L1 expression in cancer cells and PD-1 expression in NK cells and T cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6636.

Olfactory Ecto-mesenchymal Stem Cell-derived Exosomes Ameliorate Murine Sjögren's Syndrome via Suppressing Tfh Cell Response.

To investigate the effect of olfactory ecto-mesenchymal stem cell-derived exosomes (OE-MSC-Exos) on T follicular helper (Tfh) cell response and their implication in treating experimental Sjögrens syndrome (ESS). C57BL/6 mice were immunized with salivary glands (SG) proteins to induce ESS mouse model. OE-MSC-Exos were added to the Tfh cell polarization condition, and the proportion of Tfh cells was detected by FCM. The PD-L1 of OE-MSCs was silenced with small interfering RNA to extract siPD-L1-OE-MSC-Exos. We found that transfer of OE-MSC-Exos markedly attenuated disease progression and reduced Tfh cell response in mice with ESS. In culture, OE-MSC-Exos potently inhibited the differentiation of Tfh cells from naïve T cells. Moreover, OE-MSC-Exos expressed high level of the ligand for the programmed cell death protein 1 (PD-L1), knocking down PD-L1 expression in OE-MSC-Exos significantly decreased their capacity to suppress Tfh cell differentiation in vitro. Consistently, transfer of OE-MSC-Exos with PD-L1 knockdown exhibited profoundly diminished therapeutic effect in ESS mice, accompanied with sustained Tfh cell response and high levels of autoantibody production. Our results suggest that OE-MSC-Exos may exert their therapeutic effect in ameliorating ESS progression via suppressing Tfh cell response in a PD-L1-dependent manner.

Distinct antibody clones detect PD-1 checkpoint expression and block PD-L1 interactions on live murine melanoma cells

Monoclonal antibodies (abs) targeting the programmed cell death 1 (PD-1) immune checkpoint pathway have revolutionized tumor therapy. Because T-cell-directed PD-1 blockade boosts tumor immunity, anti-PD-1 abs have been developed for examining T-cell-PD-1 functions. More recently, PD-1 expression has also been reported directly on cancer cells of various etiology, including in melanoma. Nevertheless, there is a paucity of studies validating anti-PD-1 ab clone utility in specific assay types for characterizing tumor cell-intrinsic PD-1. Here, we demonstrate reactivity of several anti-murine PD-1 ab clones and recombinant PD-L1 with live B16-F10 melanoma cells and YUMM lines using multiple independent methodologies, positive and negative PD-1-specific controls, including PD-1-overexpressing and PD-1 knockout cells. Flow cytometric analyses with two separate anti-PD-1 ab clones, 29F.1A12 and RMP1-30, revealed PD-1 surface protein expression on live murine melanoma cells, which was corroborated by marked enrichment in PD-1 gene (Pdcd1) expression. Immunoblotting, immunoprecipitation, and mass spectrometric sequencing confirmed PD-1 protein expression by B16-F10 cells. Recombinant PD-L1 also recognized melanoma cell-expressed PD-1, the blockade of which by 29F.1A12 fully abrogated PD-1:PD-L1 binding. Together, our data provides multiple lines of evidence establishing PD-1 expression by live murine melanoma cells and validates ab clones and assay systems for tumor cell-directed PD-1 pathway investigations.

Vulvar cancer during pregnancy and/or breastfeeding: a report of five cases from a single center study at the University Hospital of Düsseldorf

BackgroundThe incidence of vulvar cancer (VC) in pregnancy is unknown due to its rarity; between 1955 and 2014 only 36 case reports were reported worldwide. Underreporting may also be a contributing factor to the unknown incidence of VC in pregnancy. The aim of this study was to analyze the diagnosis, treatment and outcome of vulvar cancer cases diagnosed during pregnancy and/or breastfeeding.Case presentationPatient 1 was diagnosed at 18 weeks’ gestation (WG) with Grade 2 VC (pT1a, pN0, 0/4 sentinel lymph nodes biopsy (SLNB) involved) and was treated by having the tumor resected (R0). She is currently recurrence-free at 4 years post-diagnosis.Patient 2 was diagnosed at 7 WG with Grade 2 VC (pT1b, pN1a, 1/17 SLNB, R0) and was treated during the first trimester and during the second trimester with SLNB. She is currently recurrence-free at 5 years post-diagnosis.Patient 3 was diagnosed at 30 WG with Grade 2 VC (pT1b, pN0, 0/5 SLNB, R0). She subsequently experienced a number of local recurrences postpartum that were managed by resection and is currently recurrence-free at 3 years post-diagnosis.Patient 4 was diagnosed a VL later, at 14 months during breastfeeding, that was diagnosed as Grade 3 VC (pT1b, pN1a, 1/14 SLNB, R0). The patient is currently recurrence-free at 9 years post-diagnosis.Patient 5 was not diagnosed during pregnancy, but was diagnosed with G3 VC (pT2, pN2c, 2/17 SLNB, R0) 8 months postpartum. The patient due to the extent of tumor involvement and lymph node metastasis, underwent chemoradiation therapy post-surgery. Despite adjuvant therapy, the patient progressed and developed bone metastases. Analysis of the tumour tissue revealed increased expression of PD-L1 (programmed cell death protein 1) indicating that the patient may have benefited from treatment with nivolumab to block the PD-L1 interaction; unfortunately the patient passed away at 24 months post-diagnosis before immunotherapy treatment could commence.ConclusionSurgical resection and simultaneous SLNB in VC cases are considered safe during pregnancy, with comparable outcomes to non-pregnant women. Prompt diagnostic workup and treatment should never be delayed during pregnancy as delayed diagnosis could lead to tumour progression with fatal consequences.

Immunotherapy in Gastric Cancer.

Immune checkpoint inhibition is a new standard of targeted therapy in the treatment of advanced or metastatic gastric cancer (GC) and is represented in various combinations with and without chemotherapy in every therapy line within clinical trials. In advanced adenocarcinoma of GC, gastroesophageal junction cancer (GEJC) and esophageal cancer (EC), the combination of nivolumab and chemotherapy in first-line therapy improves overall survival (OS) in PD-L1 (programmed cell death protein 1)-positive patients with approval in Europe (PD-L1 CPS (combined positivity score) ≥ 5), USA and Taiwan (CHECKMATE-649) and pembrolizumab plus chemotherapy for GEJC and EC in Europe (CPS ≥ 10) and the USA (KEYNOTE-590). Furthermore, pembrolizumab plus trastuzumab and chemotherapy show clear benefits in OS and are approved as first-line treatment of Her2 (human epidermal growth factor receptor-2)-positive tumors in the USA (KEYNOTE-811). Nivolumab demonstrates superior OS regardless of PD-L1 expression in third-line therapy with approval in Japan (ATTRACTION-02) and pembrolizumab prolonged the duration of response in PD-L1 positive patients with approval in the USA in PD-L1 CPS ≥ 1 patients (KEYNOTE-059). This review reflects the rationale and current results of phase II and III clinical trials investigating various immune checkpoint inhibitors targeting PD-L1/1 and CTLA (anticytotoxic T-lymphocyte-associated antigen)-4 in combination with and without chemotherapy and Her2-targeted therapy in GC.

Perspectives on the role of breast cancer susceptibility gene in breast cancer.

Breast cancer susceptibility gene 1/2 can repair damaged DNA through homologous recombination. Besides, the local immune microenvironment of breast cancer is closely linked to the prognosis of patients. But the relationship of breast cancer susceptibility gene 1/2 expression and local immunosuppressive microenvironment in breast cancer is not clear. The aim of this study was to discuss the correlation between them. The fresh primary breast tumors and paired normal tissues of 156 cases of breast cancer patients as well as peripheral blood of 156 cases among them in Tianjin Medical University Cancer Institute and Hospital from January 2014 to October 2018 were collected. The association between breast cancer susceptibility gene 1/2 germline mutation and immune status of microenvironment in situ was analyzed. The results indicated that the germline mutation of breast cancer susceptibility gene 1/2 was inconsistent with the breast cancer susceptibility gene 1/2 protein expression, and the proportion of immune cells in patients with negative expression of breast cancer susceptibility gene 1/2 protein was higher than patients with positive expression of breast cancer susceptibility gene 1/2 protein (p < 0.05). And the expression of programmedcelldeathprotein1, cytotoxic T-Lymphocyte Antigen 4, programmed deathligand-1 of CD3+ T cells in patients with negative expression of breast cancer susceptibility gene 1/2 protein was higher than patients with positive expression of breast cancer susceptibility gene 1/2 protein (p < 0.05). The breast cancer susceptibility gene 1 protein expression was significantly correlated with family history of breast cancer patients (p = 0.006), local lymph node metastases (p = 0.001), and TNM staging (p ≤ 0.001). The breast cancer susceptibility gene 2 protein expression was significantly related to local lymph node metastases (p ≤ 0.001), III stage rate(p = 0.003) and molecular subtyping (p ≤ 0.001). Besides, the 5years diseasefreesurvival was worse for G1 group and pathological III stage patients than other groups and other TNM stage patients. In short, the immune therapy may be a potential therapy method for breast cancer patients with negative expression of breast cancer susceptibility gene 1/2 protein.

The Role of Peripheral CD4+PD-1+ and CD8+PD-1+ T Lymphocytes in Triple Negative Breast Cancer Patients

Programmed cell death protein-1 and programmed death ligand-1 pathway activation play a vital role that can be modulated by tumor cells to blunt host immune surveillance. Periphery programmed cell death protein-1 expression level on cluster of differentiation 4+ and cluster of differentiation 8+ T lymphocytes of 185 female patients first diagnosed with triple negative breast cancer in Tianjin Medical University Cancer Institute and Hospital were analyzed by multicolor flow cytometry prior to any anti-tumor treatment. Patients who received chemotherapy alone for 2-8 cycles and received sequential samples were assessed with response evaluation criteria in solid tumors 1.1. Peripherally, the rate of cluster of differentiation 4+ programmed cell death protein-1+ and cluster of differentiation 8+ programmed cell death protein-1+ lymphocytes in general group were significantly higher than in the control group (p<0.0001). Post treatment programmed cell death protein-1 expression level on cluster of differentiation 4+ T lymphocytes and cluster of differentiation 8+ T lymphocytes was significantly lower than the baseline level in better response to neoadjuvant chemotherapy group (all p<0.05). In the contrary, programmed cell death protein-1 expression on both cluster of differentiation 4+ T lymphocytes and cluster of differentiation 8+ T lymphocytes showed no difference between pretreatment and post treatment in triple negative breast cancer patients with poor response to neoadjuvant treatment (all p>0.05). Peripheral cluster of differentiation 4+ programmed cell death protein-1+ and cluster of differentiation 8+ programmed cell death protein-1+ T lymphocytes of patients with triple negative breast cancer are associated with clinical response to neoadjuvant treatment.

Comprehensive analysis of PD-L1 expression, tumor-infiltrating lymphocytes, and tumor microenvironment in LUAD: differences between Asians and Caucasians

BackgroundsThe characteristics of programmed cell death protein-1 (PD-L1) expression, tumor-infiltrating lymphocytes (TILs), and tumor microenvironment (TME) in lung adenocarcinoma (LUAD) patients are closely related to immunotherapy, and there are differences between Asians and Caucasians.MethodsAcquire the transcriptome data of the Cancer Genome Atlas and Chinese LUAD patients. R software was used to analyze the differential expression of genes, prognosis, and gene function. Use CIBERSORT for TIL-related analysis and ESTIMATE for TME-related analysis.ResultsThe expression of PD-L1 in tumor tissues of Caucasian LUAD patients was lower than that in normal tissues, while there was no significant difference in Asians. There was no statistical difference between PD-L1 expression and prognosis. The composition of TILs between Caucasian and Asian LUAD patients was quite different. There was no correlation between TILs and prognosis in Caucasians. However, the higher content of resting mast cells indicated a better prognosis in Asians. The Caucasian patients with higher immune and estimate scores had a better prognosis (p = 0.021, p = 0.025). However, the Asian patients with a higher estimate score had a worse prognosis (p = 0.024). The high expression of COL5A2 (p = 0.046, p = 0.027) and NOX4 (p = 0.020, p = 0.019) were both associated with the poor prognosis in Caucasians and Asians.ConclusionThere are many differences in the characteristics of PD-L1 expression, TILs, and TME between Caucasian and Asian LUAD patients. This provides a certain hint for the selection of specific immunotherapy strategies separately for Caucasian and Asian LUAD patients.

Extracellular acidity in tumor tissue upregulates programmed cell death protein1 expression on tumor cells via proton-sensing G protein-coupled receptors.

Acidity in the tumor microenvironment has been reported to promote cancer growth and metastasis. In our study, we examined a potential relation between extracellular acidity and expression level of the immune checkpoint molecule programmed cell death protein1 (PD-L1) in murine squamous cell carcinoma (SCC) and melanoma cell lines. PD-L1 expression in the tumor cells was upregulated by culturing in a low pH culture medium. Tumor-bearing mice were allowed to ingest sodium bicarbonate, resulting in neutralization of acidity in the tumor tissue, a decrease in PD-L1 expression in tumor cells and suppression of tumor growth in vivo. Proton-sensing G protein-coupled receptors, T-cell death-associated gene 8 (TDAG8) and ovarian cancer G-protein-coupled receptor 1 (OGR1), were upregulated by low pH, and essentially involved in the acidity-induced elevation of PD-L1 expression in the tumor cells. Human head and neck SCC RNAseq data from the Cancer Genome Atlas also suggested a statistically significant correlation between expression levels of the proton sensors and PD-L1 mRNA expression. These findings strongly suggest that neutralization of acidity in tumor tissue may result in reduction of PD-L1 expression, potentially leading to inhibition of an immune checkpoint and augmentation of antitumor immunity.

A Novel Immunotype-based Risk Stratification Model Predicts Postoperative Prognosis and Adjuvant TACE Benefit in Chinese Patients with Hepatocellular Carcinoma.

Background and Aims: The tumor microenvironment can be divided into inflamed, immune-excluded and immune-desert phenotypes according to CD8+ T cell categories with differential programmed cell death protein 1 (PD-L1) expression. The study aims to construct a novel immunotype-based risk stratification model to predict postsurgical survival and adjuvant trans-arterial chemoembolization (TACE) response in patients with hepatocellular carcinoma (HCC).Methods: A total of 220 eligible HCC patients participated in this study. CD8+ T cell infiltration and PD-L1 expression mode were estimated by immunohistochemical staining. A risk stratification model was developed and virtualized by a nomogram that integrated these independent prognostic factors. The postoperative prognosis and adjuvant TACE benefits were evaluated with a novel immunotype-based risk stratification model.Results: A total of 220 patients were finally identified. Immune-desert, immune-excluded, and inflamed immunotypes represented 45%, 24%, and 31% of HCC, respectively. Univariate and multivariate analyses identified immunotype and PD-L1 expression mode as independent prognostic factors for overall survival time (OS) and recurrence-free survival time (RFS). The nomogram was constructed by integrating immunotype, PD-L1 expression, Barcelona Clinic Liver Cancer (BCLC) stage and tumor grade. The C-index was 0.794 in the training cohort and 0.813 in the validation cohort. A risk stratification system was constructed based on the nomogram classifying HCC patients into 3 risk groups. The average OS times in the low-risk, intermediate-risk and high-risk groups in all cohorts were 77.1 months (95% CI 71.4-82.9), 53.7 months (95% CI 48.2-59.2), and 25.6 months (95% CI 21.4-29.7), respectively. Further analysis showed that OS was significantly improved by adjuvant TACE in the low- and intermediate-risk groups (P=0.041 and P=0.010, respectively) but not in the high-risk group (P=0.398).Conclusion: A novel immunotype-based risk stratification model was built to predict postoperative prognosis and adjuvant TACE benefit in HCC patients. These tools can assist in building a more customized method of HCC treatment.

HGF-Induced PD-L1 Expression in Head and Neck Cancer: Preclinical and Clinical Findings.

Head and neck squamous cell carcinoma (HNSCC) is a widespread disease with a low survival rate and a high risk of recurrence. Nowadays, immune checkpoint inhibitor (ICI) treatment is approved for HNSCC as a first-line treatment in recurrent and metastatic disease. ICI treatment yields a clear survival benefit, but overall response rates are still unsatisfactory. As shown in different cancer models, hepatocyte growth factor/mesenchymal–epithelial transition (HGF/Met) signaling contributes to an immunosuppressive microenvironment. Therefore, we investigated the relationship between HGF and programmed cell death protein 1 (PD-L1) expression in HNSCC cell lines. The preclinical data show a robust PD-L1 induction upon HGF stimulation. Further analysis revealed that the HGF-mediated upregulation of PD-L1 is MAP kinase-dependent. We then hypothesized that serum levels of HGF and soluble programmed cell death protein 1 (sPD-L1) could be potential markers of ICI treatment failure. Thus, we determined serum levels of these proteins in 20 HNSCC patients before ICI treatment and correlated them with treatment outcomes. Importantly, the clinical data showed a positive correlation of both serum proteins (HGF and sPD-L1) in HNSCC patient’s sera. Moreover, the serum concentration of sPD-L1 was significantly higher in ICI non-responsive patients. Our findings indicate a potential role for sPD-L1 as a prognostic marker for ICI treatment in HNSCC.

1896MO Volumetric PET response assessment outperforms conventional criteria in patients receiving high-dose pembrolizumab for malignant mesothelioma

Fixed-dose pembrolizumab (200 mg abs., d1, q3w) for the treatment of malignant pleural mesothelioma did not result in survival benefit in the phase 3 PROMISE-meso trial compared to 2nd-line chemotherapy. Due to lack of validated imaging response criteria, responder-subgroups with potential survival benefit have not yet been identified. Here, we administered high-dose pembrolizumab (10 mg/kg, d1, q2w) considering the KEYNOTE-028 trial and assessed the prognostic value of PET metabolic response in patients with chemotherapy-resistant malignant mesothelioma of the pleura or peritoneum. Data from 27 patients with baseline and follow-up 18F-FDG PET/CT imaging were retrospectively analyzed. RECIST v1.1, mRECIST, PERCISTSULpeak and PERCISTMTV were used separately to categorize responders in CT and PET imaging studies. Progression-free survival (PFS) and overall survival (OS) of responders were compared to non-responders using Kaplan-Meier and log-rank analyses. Programmed Cell Death Protein 1 (PD-L1) expression status was assessed and its association with outcome was investigated. 27 patients had 18F-FDG-PET/CT imaging at baseline and after at least 4 cycles pembrolizumab. Median PFS and OS were 3.4 and 15.1 months, respectively. Response rates were 7%, 7%, 30%, and 30% based on RECIST v1.1, mRECIST, PERCISTSULpeak, and PERCISTMTV response criteria, respectively. Response according to PERCISTMTV predicted prolonged OS or PFS (p < 0.01), whereas all other imaging criteria and PD-L1 expression did not. 18F-FDG PET metabolic volume response predicts survival in patients with malignant mesothelioma receiving high-dose pembrolizumab. These results should prompt inclusion of PET response assessment in future phase 3 clinical trials.

Genomic correlates and classification of PD-L1 status in non-small cell lung cancer.

e21578 Background: Programmed cell death 1 (PD-L1) is the first FDA-approved predictive biomarker for non-small cell lung cancer (NSCLC) patients treated with PD-(L)1 blockade therapy. Herein, we aim to identify potential anti-PD-L1 treatment-related biomarkers through evaluating the correlation between the PD-L1 expression level, clinical characteristics, and the mutational profile of a large Chinese NSCLC cohort. Methods: Genomic profiling of tumor biopsies from a total of 808 Chinese NSCLC patients, including 651 adenocarcinomas (ADCs) and 157 squamous cell carcinomas (SCCs), was performed using next-generation sequencing by targeting 425 cancer-relevant genes. Immunohistochemical analysis was used to evaluate PD-L1 protein expression using PD-L1 antibodies including DAKO 22C3 ( N= 695) and DAKO 28-8 ( N= 113), respectively. Results: The PD-L1 positive ( &gt; 1%) rate was 49.2% in ADCs and 52.9% in SCCs, respectively. PD-L1 expression (22C3) was associated with the male gender( p&lt; 0.01) and lymph node metastasis ( p= 0.048) in ADCs but not in SCC patients. PD-L1 expression (22C3) was inversely correlated with KRAS wildtype ( p&lt; 0.001) and EGFR exon 19 deletion( p&lt; 0.01) in ADC, while it was negatively associated with TP53 oncogenic mutations ( p= 0.049) in SCC. Copy number variation analysis revealed that MDM2 amplification ( p= 0.027), 1q gain ( p= 0.012), and 5q deletion ( p&lt; 0.01) negatively correlated with PD-L1 expression, whereas PD-L1 and PD-L2 amplification ( p&lt; 0.001 and p&lt; 0.0001) were positively associated with PD-L1 expression in ADCs. In SCCs, PD-L1 expression (22C3) was negatively associated with copy number gain in EGFR ( p= 0.040), MDM2 ( p= 0.044), 14q ( p= 0.032), and 20q ( p= 0.026), along with PTPRD loss (p = 0.015) and 19p deletion (p = 0.025). However, it was positively associated with 9p amplification ( p&lt; 0.01) and 13q deletion ( p= 0.019). Plus, KIF5B- RET ( p= 0.006) appeared to be inversely related to the PD-L1 expression levels (22C3) in ADCs alone. In addition, these predicted biomarkers were used to delineate the receiver operating characteristic (ROC) calculation to discriminate between PD-L1 low and high (22C3, 50%) with an AUC score of 0.779. Lastly, PD-L1 expression (28-8) did not show significant correlation with any detected oncogenic mutations, but negatively correlated with NKX2-1 gain ( p= 0.0379) and 9q deletion ( p= 0.0379) in ADCs. Conclusions: This study revealed the correlation between PD-L1 protein expression, clinical features, and mutational traits in NSCLC patients, and provided a classifier for PD-L1 expression prediction.

Prolonged Antiretroviral Therapy in Adolescents With Vertical HIV Infection Leads to Different Cytokine Profiles Depending on Viremia Persistence.

We investigated immune activation, exhaustion markers and cytokine expression upon stimulation in adolescents with vertical HIV infection. Thirty adolescents receiving antiretroviral therapy (ART) for vertical HIV infection, including 12 with detectable viral load (HIV/DET), 18 with undetectable viral load (HIV/UND) and 30 control adolescents without HIV infection (CONTROL), were evaluated for immune activation and programmed cell death protein-1 expression by flow cytometry, and 21 cytokines by Luminex Multiple Analyte Profiling technology after in vitro peripheral blood phytohemagglutinin stimulation. Lower CD4 T cells and higher T cell activation and exhaustion markers were noted on CD4 T and on CD8 T cells and memory subsets from HIV/DET group, who also produced lower in vitro IFN-gamma, IL-10, IL-13, IL-17A, IL-5 and IL-6 than HIV/UND group. HIV/UND were comparable with CONTROL group in respect to CD4 T cell counts and T cell activation and exhaustion markers, but with higher in vitro production of ITAC (a chemokine with leukocyte recruitment function), IL-4 and IL-23. An inverse correlation between cytokine production and programmed cell death protein-1 expression on CD4 T and CD8 T subsets was detected. Persistent viremia despite ART leads to T cell activation and immune exhaustion with low cytokine production, whereas viral suppression by ART leads to parameters similar to CONTROL, although a different cytokine profile is observed, indicating residual HIV impact despite absence of detectable viremia.