Death Receptor Ligand Research Articles

Ongoing Evaluation of Immune-related Response Assessment in Brain Metastases

脑转移瘤是成人恶性神经系统肿瘤最常见的病因。针对这一部分人群，治疗手段有限，预后不佳。近年来，以程序性死亡受体1（programmed cell death protein 1, PD-1）及程序性死亡受体配体1（programmed cell death protein ligand 1, PD-L1）抑制剂为主的免疫治疗，给恶性肿瘤的治疗模式带来了革新。免疫检查点抑制剂（immune checkpoint inhibitors, ICIs）彻底改变了晚期非小细胞肺癌（non-small cell lung cancer, NSCLC）的治疗模式。ICI在某些驱动基因阴性的NSCLC脑转移瘤治疗中，取得了令人鼓舞的结果。然而，针对脑转移瘤患者的临床研究，不仅相应的临床数据有限，其疗效的评价也缺乏统一标准。本文旨在阐述不同的疗效评价标准及其在临床研究中的应用，比较之间的异同，并对未来发展趋势进行展望。

Role of apoptosis repressor with caspase recruitment domain (ARC) in cell death and cardiovascular disease.

Apoptosis repressor with caspase recruitment domain (ARC) is a highly effective and multifunctional inhibitor of apoptosis that is mainly expressed in postmitotic cells such as cardiomyocytes and skeletal muscle cells. ARC contains a C-terminal region rich in proline and glutamic acid residues and an N-terminal caspase recruitment domain (CARD). The CARD is originally described as a protein-binding motif that interacts with caspase through a CARD-CARD interaction. Initially, the inhibitory effect of ARC was only found in apoptosis, however, it was later found that ARC also played a regulatory role in other types of cell death. As a powerful cardioprotective factor, ARC can protect the heart by inhibiting the death of cardiomyocytes in various ways. ARC can reduce the cardiomyocyte apoptotic response to various stresses and injuries, including extrinsic apoptosis induced by death receptor ligands, cellular Ca2+ homeostasis and the dysregulation of endoplasmic reticulum (ER) stress, oxidative stress and hypoxia. In addition, changes in ARC transcription and translation levels in the heart can cause a series of physiological and pathological changes, and ARC can also perform corresponding functions through interactions with other molecules. Although there has been much research on ARC, the functional redundancy among proteins shows that ARC still has much research value. This review summarizes the molecular characteristics of ARC, its roles in the various death modes in cardiomyocytes and the roles of ARC in cardiac pathophysiology. This article also describes the potential therapeutic effect and research prospects of ARC.

Histopathological Subtypes and PD-L1 Expression in Primary Urethral Adenocarcinoma: A Series of 5 Cases

Urethral adenocarcinoma is a rare disease with poor prognosis that can display multiple histologic patterns and has an unclear histogenesis. Radical surgery with extensive periurethral resection is the preferred therapeutic approach. Both chemotherapy and radiotherapy have been used as complementary treatment options. Due to the tendency of these tumors to recur, treatment-associated complications, and the limited choice of therapeutic options, patient management can be difficult. Given the lack of literature regarding immunotherapy in urethral adenocarcinoma, our objective was to explore the expression of programmed death receptor-ligand 1 (PD-L1) throughout the different histological subtypes of primary urethral adenocarcinoma. We reviewed all primary urethral adenocarcinomas diagnosed at our hospital between 1965 and 2019, performed immunohistochemical assays on the tissue blocks, classified them according to their histology and origin, and performed PD-L1 (22C3) immunohistochemistry assays in all cases. We found a total of 5 cases of primary urethral adenocarcinoma. All of the patients were women. One of the cases was a cribriform adenocarcinoma, 2 were columnar-mucinous adenocarcinomas, and 2 were clear cell adenocarcinomas. One of the clear cell adenocarcinomas strongly expressed PD-L1. In addition, a profuse inflammatory infiltration constituted by CD3-positive and CD8-positive T lymphocytes within tumor cells was observed in this case. None of the other cases showed PD-L1 expression. In conclusion, some urethral adenocarcinomas may strongly express PD-L1 and thus could potentially allow the use of immunotherapy in selected cases of advanced or recurrent adenocarcinoma.

Glucose metabolism involved in PD-L1-mediated immune escape in the malignant kidney tumour microenvironment

Programmed death receptor-ligand 1 (PD-L1) plays a crucial role in immune evasion by tumour cells. Most tumour cells exhibit energy dependency and acquire energy from glycolysis. However, the relationship between glucose metabolism and PD-L1 expression remains unclear. In this study, changes in PD-L1 expression in renal carcinoma cells were evaluated during glucose deficiency and recovery, and PD-L1 could inversely regulate glycolysis. In addition, the possible signalling pathways activated by a low level of glucose to regulate PD-L1 were tested experimentally. The results showed that glucose deficiency could upregulate PD-L1 expression in two renal cancer cell lines, 786-O and OS-RC-2. Although the native levels of PD-L1 differed in the two cell lines, the upregulated PD-L1 expression was repristinated after glucose recovery. Moreover, epidermal growth factor receptor (EGFR) expression was upregulated in both cell lines with glucose deficiency. The use of an EGFR inhibitor reversed the upregulation of PD-L1 expression induced by glucose deficiency and inhibited the phosphorylation of extracellular regulated protein kinases 1 and 2 (ERK1/2). EGFR activated by epidermal growth factor (EGF) induced PD-L1 expression and ERK1/2 phosphorylation. Furthermore, an ERK1/2 inhibitor inhibited the phosphorylation of c-Jun and decreased the elevated PD-L1 expression induced by glucose deficiency. In addition, this study also showed that 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase 3 (PFK-2/FBPase 3 or PFKFB3) mediated upregulation of the level of glycolysis to improve the adverse environment through PD-L1 induction. Therefore, glucose metabolism can regulate the expression of PD-L1 through the EGFR/ERK/c-Jun pathway in renal cancer, and elevated PD-L1 can also regulate glycolysis by improving the expression of PFKFB3. The findings of this study could provide a new multiple target treatment for renal cell carcinoma (RCC) therapy.

Gut-licensed IFNγ+ NK cells drive LAMP1+TRAIL+ anti-inflammatory astrocytes.

Astrocytes are glial cells that are abundant in the central nervous system (CNS) and that have important homeostatic and disease-promoting functions1. However, little is known about the homeostatic anti-inflammatory activities of astrocytes and their regulation. Here, using high-throughput flow cytometry screening, single-cell RNA sequencing and CRISPR-Cas9-based cell-specific in vivo genetic perturbations in mice, we identify a subset of astrocytes that expresses the lysosomal protein LAMP12 and the death receptor ligand TRAIL3. LAMP1+TRAIL+ astrocytes limit inflammation in the CNS by inducing T cell apoptosis through TRAIL-DR5 signalling. In homeostatic conditions, the expression of TRAIL in astrocytes is driven by interferon-γ (IFNγ) produced by meningeal natural killer (NK) cells, in which IFNγ expression is modulated by the gut microbiome. TRAIL expression in astrocytes is repressed by molecules produced by T cells and microglia in the context of inflammation. Altogether, we show that LAMP1+TRAIL+ astrocytes limit CNS inflammation by inducing T cell apoptosis, and that this astrocyte subset is maintained by meningeal IFNγ+ NK cells that are licensed by the microbiome.

Bile Acid Toxicity and Protein Kinases.

If the bile acids reach to pathological concentrations due to cholestasis, accumulation of hydrophobic bile acids within the hepatocyte may result in cell death. Thus, hydrophobic bile acids induce apoptosis in hepatocytes, while hydrophilic bile acids increase intracellular adenosine 3',5'-monophosphate (cAMP) levels and activate mitogen-activated protein kinase (MAPK) and phosphoinositide 3-kinase (PI3K) pathways to protect hepatocytes from apoptosis.Two apoptotic pathways have been described in bile acids-induced death. Both are controlled by multiple protein kinase signaling pathways. In mitochondria-controlled pathway, caspase-8 is activated with death domain-independent manner, whereas, Fas-dependent classical pathway involves ligand-independent oligomerization of Fas.Hydrophobic bile acids dose-dependently upregulate the inflammatory response by further stimulating production of inflammatory cytokines. Death receptor-mediated apoptosis is regulated at the cell surface by the receptor expression, at the death-inducing signaling complex (DISC) by expression of procaspase-8, the death receptors Fas-associated death domain (FADD), and cellular FADD-like interleukin 1-beta (IL-1β)-converting enzyme (FLICE) inhibitory protein (cFLIP). Bile acids prevent cFLIP recruitment to the DISC and thereby enhance initiator caspase activation and lead to cholestatic apoptosis. At mitochondria, the expression of B-cell leukemia/lymphoma-2 (Bcl-2) family proteins contribute to apoptosis by regulating mitochondrial cytochrome c release via Bcl-2, Bcl-2 homology 3 (BH3) interacting domain death agonist (Bid), or Bcl-2 associated protein x (Bax). Fas receptor CD95 activation by hydrophobic bile acids is initiated by reduced nicotinamide adenine dinucleotide phosphate (NADPH) oxidase-dependent reactive oxygen species (ROS) signaling. However, activation of necroptosis by ligands of death receptors requires the kinase activity of receptor interacting protein1 (RIP1), which mediates the activation of RIP3 and mixed lineage kinase domain-like protein (MLKL). In this chapter, mainly the effect of protein kinases signal transduction on the mechanisms of hydrophobic bile acids-induced inflammation, apoptosis, necroptosis and necrosis are discussed.

MicroRNA-142-5p Suppresses Proliferation and Invasion of Non-Small Cell Lung Cancer Cells by Targeting Programmed Cell Death Receptor Ligand 1

Lung cancer is one of the most deadly tumor disease in the world and most lung cancer is non-small cell lung cancer. MicroRNAs are considered as a variety of endogenous non-coding RNA, acting as interference during the process after transcription of gene. Recently, microRNA-142-5p, one of the microRNAs, was reported to enhance anti-tumor immune of non-small cell lung cancer cells by targeting programmed cell death receptor ligand 1. Programmed cell death receptor ligand 1 was also believed to be a regulator of cell proliferation and migration. However, the effect of microRNA-142-5p on proliferation and invasion of non-small cell lung cancer cells via regulating programmed cell death receptor ligand 1 was still unknown. Thus, this study demonstrated that there was low expression level of microRNA-142-5p in different nonsmall cell lung cancer cell lines. Programmed cell death receptor ligand 1 was proved to be the target gene of microRNA-142-5p and microRNA-142-5p also had negative correlation with programmed cell death receptor ligand 1. The high expression of microRNA-142-5p lead to suppression of proliferation and invasion in non-small cell lung cancer cells by down regulation of programmed cell death receptor ligand 1. The mechanism of microRNA-142-5p affecting proliferation and invasion of non-small cell lung cancer cells via targeting programmed cell death receptor ligand 1 might give a new thought of tumor therapy.

Correlation between PD-L1 expression ON CTCs and prognosis of patients with cancer: a systematic review and meta-analysis

ABSTRACT Circulating tumor cells (CTCs) are considered to be related to the prognosis of cancer patients. CTC is a powerful indicator for recurrence or metastasis. The relationship, however, between the expression of programmed cell death receptor ligand 1 (PD-L1) on CTCs in peripheral blood and the prognosis, is still controversial. Here, we conducted a meta-analysis to evaluate its prognostic value. A total of 20 articles were screened from PubMed, Embase, Cochrane, China National Knowledge Internet (CNKI) and WanFang Database, and the Hazard Ratio (HR) along with 95% confidence intervals (CIs) of each article were combined to study the relationship between PD-L1 expression on CTCs and prognosis. The expression of PD-L1 on CTCs in the peripheral blood of cancer patients is associated with poor prognosis. The pooled HRs for overall survival (OS) in cancer patients were 1.85 (95% CI, 1.29–2.66, P = .001). The pooled HRs for progression-free survival (PFS) in cancer patients were 1.50 (95% CI, 1.12–2.01; P = .007). This is the first meta-analysis to clarify the expression of PD-L1 on CTCs at baseline affects the prognosis of cancer patients. Patients with CTCs expressing PD-L1 had a shorter survival time than patients with CTCs not expressing PD-L1.

Adverse effects of immune checkpoint inhibitor therapies on right ventricular function and pulmonary arterial dilatation.

Immunologic risk factors contribute to endothelial dysfunction and development of pulmonary vascular disease. Immune checkpoint inhibitors, used as immunotherapies for malignancies, have a wide range of reported immune-related adverse events. We retrospectively describe the impact of immune checkpoint inhibitors on the development of pulmonary vascular injury and right ventricular dysfunction as compared across both computed tomography and transthoracic echocardiography. Twenty-four of 389 patients treated with immune checkpoint inhibitors at a single academic center between 2015 and 2019 were evaluated. Thirteen (54%) patients were treated with anti-programmed cell death receptor 1 (PD-1), 8 (33%) with anti-programmed death receptor ligand 1 (PD-L1) therapy, and 3 (13%) with combination anti-PD-1 and anti-cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) therapy. At a median of 85 days of immune checkpoint inhibitor therapy, RVfwLS significantly increased from –20.6% to –16.7% (p = 0.002). After a median of 59 days of immune checkpoint inhibitor therapy, median pulmonary artery to aorta ratio worsened from 0.83 to 0.89 (p = 0.03). There was an correlation of duration of immune checkpoint inhibitor therapy (β = –0.574, p = 0.003) with percent change in RVfwLS. Patients who received anti-PD-1 therapy (β = –0.796, p = 0.001) showed the greatest correlation of duration of immune checkpoint inhibitor therapy with percent change in RVfwLS. Exposure to immune checkpoint inhibitors are associated with RV dysfunction and vascular changes as measured by strain and computed tomography, respectively.

Mitochondrial Mechanisms of Necroptosis in Liver Diseases.

Cell death represents a basic biological paradigm that governs outcomes and long-term sequelae in almost every hepatic disease. Necroptosis is a common form of programmed cell death in the liver. Necroptosis can be activated by ligands of death receptors, which then interact with receptor-interactive protein kinases 1 (RIPK1). RIPK1 mediates receptor interacting receptor-interactive protein kinases 3 (RIPK3) and mixed lineage kinase domain-like protein (MLKL) and necrosome formation. Regarding the molecular mechanisms of mitochondrial-mediated necroptosis, the RIPK1/RIPK3/MLKL necrosome complex can enhance oxidative respiration and generate reactive oxygen species, which can be a crucial factor in the susceptibility of cells to necroptosis. The necrosome complex is also linked to mitochondrial components such as phosphoglycerate mutase family member 5 (PGAM5), metabolic enzymes in the mitochondrial matrix, mitochondrial permeability protein, and cyclophilin D. In this review, we focus on the role of mitochondria-mediated cell necroptosis in acute liver injury, chronic liver diseases, and hepatocellular carcinoma, and its possible translation into clinical applications.

Pilot Study of the Performance of 19-G Needle in Endobronchial Ultrasound-guided Transbronchial Aspiration for the Diagnosis and Testing of Molecular Markers in Lung Cancer.

Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) has become the standard for diagnosis and staging of lung cancer. Historically, 21- and 22-G needles have been paired with EBUS. We evaluated the performance of EBUS-TBNA using a larger 19-G needle in the assessment of tumor tissue obtained and success of testing for molecular markers. We prospectively enrolled adult patients with lymphadenopathy concerning for metastatic lung cancer. Patients underwent diagnostic EBUS-TBNA utilizing 19-G needles. Cases of non-small cell lung cancer (NSCLC) were evaluated for programmed cell death receptor ligand (PD-L1) expression. Cases of adenocarcinoma or undifferentiated NSCLC were further evaluated for 3 molecular markers for driver mutations: epidermal growth factor receptor (EGFR), c-ros oncogene 1 (ROS-1), and anaplastic lymphoma kinase (ALK). Fifty patients were enrolled and underwent EBUS-TBNA using 19-G needles. PD-L1 assay was successfully performed in 90% of NSCLC cases. In adenocarcinoma or undifferentiated NSCLC cases, the success rate in testing was 90% for EGFR and 86% for ALK. ROS-1 testing had a success rate of 67%; 24% of these specimens had adequate tumor cells but there was technical difficulty with the assay. Block quality was judged by total number of tumor cells per hematoxylin and eosin-stained slide of each cell block (58% of specimens had >500 cells and 22% had 200 to 500 cells). There were no adverse events. EBUS-TBNA using 19-G needles can obtain a high number of tumor cells and has a high rate of success in performing assays for PD-L1, EGFR, and ALK in NSCLC patients without an increase in adverse events. The success rate of ROS-1 testing was lower.

Proteolysis targeting chimera (PROTAC) for epidermal growth factor receptor enhances anti-tumor immunity in non-small cell lung cancer.

While immunotherapy has dramatically revolutionized the treatment of non-small cell lung cancer (NSCLC), it still faces challenges such as low therapeutic efficacy and immune-related adverse events, indicating that safe and effective approaches to enhance NSCLC immunotherapy are still highly demanded. Epidermal growth factor receptor (EGFR) is an established target for molecularly targeted therapy of NSCLC. Overexpression and activating mutations of EGFR can promote the resistance of NSCLC to immunotherapy via upregulating inhibitory immune checkpoints such as programmed death receptor ligand 1 (PD-L1) and indoleamine-2,3-dioxygenase-1 (IDO1). Thus, therapeutic inhibition of EGFR also holds promise in modulating the immune microenvironment to advance NSCLC immunotherapy. In this study, we employed a proteolysis targeting chimera (PROTAC) that degrades EGFRL858R to investigate its potential in dually inhibiting PD-L1 and IDO1 to potentiate the anti-tumor immunity in NSCLC. We demonstrated that PROTAC significantly downregulated the protein levels of both PD-L1 and IDO1 in NSCLC H3255 cell and tumor. We also confirmed that PROTAC significantly suppressed the H3255 tumor growth and enhanced the anti-tumor immune response in H3255 tumor. Overall, our study provides a novel strategy for future NSCLC therapy.

Cell Density of NK Cells during Ex Vivo Expansion Impacts NK Cell Surface TRAIL Expression

Introduction Natural Killer (NK) cells are an emerging form of cancer immunotherapy currently being tested in clinical trials world-wide. NK cells are innate immune cells that can kill tumor cells via release of cytotoxic granules and via surface expression of the death receptor ligands tumor-related apoptosis-inducing ligand (TRAIL) and Fas ligand. We and others have recently shown that the proteasome inhibitor bortezomib sensitizes tumor cells to NK cell TRAIL-mediated killing by upregulation of death receptor 5. In a recent phase I NK cell dose-escalation study conducted at the NIH (NCT00720785) we have attempted to exploit TRAIL sensitization by administering ex vivo-expanded autologous NK cells to patients with solid tumors or hematologic malignancies that have been pretreated with bortezomib. Ex vivo cultures used to expand clinical grade NK cells for this trial utilize irradiated EBV-LCL feeder cells and IL-2 containing media which upregulates surface expression of TRAIL, substantially augmenting NK cell killing of bortezomib-treated tumors in vitro. Here we characterize the impact of specific expansion conditions used to generate high numbers of NK cells for clinical use on NK cell TRAIL expression. Methods To generate clinical grade ex vivo-expanded NK cells, we first isolated NK cells from patient apheresis products by CD3+ depletion followed by CD56+ selection, and stimulated these enriched NK cells with irradiated EBV-LCL feeder cells at a ratio of 1:10 in X-VIVO 20 supplemented with 10% inactivated human AB serum and recombinant human IL-2 (500 IU/ml). The clinical trial evaluated 8 escalating NK cell dose levels (Figure 1). Cohorts 1-4 received a single infusion of ex vivo-expanded NK cells on day 0 in a dose-escalating fashion (3-6 pts per cohort) and cohorts 5-7 received 1 x 108 NK cells/kg on day 0 and a second escalating dose of NK cells infused on day +5. A "closed bag" Baxter PL732 culture system was used for cohorts 1-7 which was later changed to a GREX500-CS (Wilson Wolf) system in cohorts 7-8. Using flow cytometry, we monitored surface expression of TRAIL on the day NK cells were harvested and infused fresh into patients. We also assessed TRAIL expression on NK cells from a single patient cultured at 6 different cell densities (range: 2.03-16.95 x 106/cm2) using culture conditions mimicking the phase I trial. Results A total of 137 NK cell cultures were harvested and administered fresh to 32 patients. NK cells on the day of harvest expanded a median of 198-fold, 895-fold, and 3637-fold on culture days 14-16, 19-22, and 24-27, respectively. NK cells at harvest contained a median of 99.7% CD3−/CD56+ NK cells, were 68.65% CD16+ and had a median of 88% viability. TRAIL was assessed by mean fluorescence intensity (MFI) with a median surface expression of of 1245 (range 132-4913) at the time of infusion (Figure 1). Expansions for cohort 8 generated 10-14 x109 (1 vessel) and 50-70 x109 NK cells (4-5 vessels) for fresh infusion, enough to support the target dose level of 1x108 (1st harvest) and 5x108 (2nd harvest) NK cells/kg. Remarkably, NK cells grown at higher cell density to reach the target cell numbers for cohort 8 exhibited substantially reduced TRAIL expression (median: 255, range 132-691). Subsequent experiments conducted on NK cells expanded in vitro for 14 days at different cell densities/concentrations showed TRAIL expression (MFI range: 319-1627) inversely correlated with both cell density and concentration (Figure 2). NK cells grown at the highest cell density (16.95 x 106/cm2) and concentration (4.23 x 106/mL) expressed the least amount of TRAIL (MFI 319), in contrast to those cultured at the lowest cell density (2.03 x 106/cm2) and concentration (0.51 x 106/mL), which demonstrated a TRAIL MFI of 1627. Conclusions Although ex vivo cultures using feeder cells make it possible to expand large numbers of NK cells for clinical use in humans, the higher concentrations and density of cells in these cultures reduce NK cell surface expression of TRAIL. In vitro, TRAIL expression appears to inversely correlate with cell density. These data highlight the need to avoid overly concentrating ex vivo expanded NK cells to maximize TRAIL surface expression as a method to potentiate the anticancer effects of adoptively infused NK cells. Disclosures No relevant conflicts of interest to declare.

Meta-Analysis of PD-L1 Expression As a Predictor of Survival After Checkpoint Blockade.

Programmed cell death receptor ligand 1 (PD-L1) expression is the most studied biomarker to predict the efficacy of immune checkpoint inhibitors (ICIs), but its clinical significance is controversial. We estimated the distribution of PD-L1 expression scores (ie, tumor proportion score or combined proportion score) and the relationship between PD-L1 levels and ICIs' impact on overall survival (OS). We reconstructed, pooled, and analyzed individual-level data on 7,617 patients with cancer from 14 randomized clinical trials. The effects of ICIs were quantified using differences in 24-month restricted mean survival times (ΔRMSTs; ie, the increase in life expectancy truncated at 2 years associated with ICI therapy). In a simulation study, we compared standard randomized clinical trial designs with a trial design that leverages meta-analytic results like ours. Approximately 93% of patients had a PD-L1 expression ≤ 5% (66% of patients) or > 50% (27% of patients). OS improves with ICIs regardless of PD-L1 expression level, which predicts the benefits' magnitude. For patients with non-small-cell lung cancer (NSCLC), ΔRMSTs ranged from 1.4 months (95% probability interval [PI], 0.7 to 2.2 months) for PD-L1 expression ≤ 1% to 4.1 months (95% PI, 3.2 to 5.2 months) for PD-L1 expression > 80%. For patients with non-NSCLC tumors, ΔRMSTs ranged from 0.8 months (95% PI, -0.1 to 1.7 months) to 2.3 months (95% PI, 1.3 to 4.4 months), again for PD-L1 expression levels of ≤ 1% and > 80%, respectively. Simulations suggested that designs tailored to meta-analytic results can detect the effects of ICIs in PD-L1 subgroups with higher probability (> 15%) than standard designs. The practice of dichotomizing the range of PD-L1 expression scores is inadequate for patient stratification. Meta-analytic estimates of the distribution of PD-L1 scores and subgroup-specific treatment effects can improve the designs of future trials of ICIs.

Innovations in targeted therapies for triple negative breast cancer.

Triple negative breast cancer (TNBC) is defined by a lack of targets, namely hormone receptor (HR) expression and human epidermal growth factor receptor 2 amplification. Cytotoxic chemotherapy remains the mainstay of treatment. Though TNBC constitutes approximately 10-15% of breast cancer, it is disproportionally lethal, but it is hoped that outcomes will improve as targetable oncogenic drivers are identified. Translational work in TNBC has focused on subsets defined by defects in homologous recombination repair, immune cell infiltration, or programmed death ligand receptor 1 expression, an over-active phosphoinositide-3 kinase pathway, or expression of androgen receptors. Though not specific to TNBC, the novel cell surface antigen trophoblast antigen 2 has also been identified and successfully targeted. This work has led to Food and Drug Administration approvals for small molecule poly-ADP-ribosyl polymerase inhibitors in patients with deleterious germline mutations in BRCA1 or BRCA2, the combination of nab-paclitaxel with immune checkpoint inhibitor antibodies in the first-line metastatic setting for programmed death ligand receptor 1+ TNBC, and use of the antibody-drug conjugate sacituzumab govitecan in the later-line metastatic setting. Identification of targetable oncogenic drivers in TNBC is an area of intense cancer biology research, hopefully translating to new therapies and improved outcomes.

Programmed Death Receptor Ligand One Expression May Independently Predict Survival In Non-Small Cell Lung Carcinoma Brain Metastases Patients Receiving Immunotherapy

Programmed death receptor ligand one (PD-L1) expression is known to predict response to PD-1/PD-L1 inhibitors in non-small cell lung cancer (NSCLC). However, the predictive role of this biomarker in brain metastases (BMs) is unknown. The aim of this study was to assess whether PD-L1 expression predicts survival in patients with NSCLC BMs treated with PD-1/PD-L1 inhibitors, after adjusting for established prognostic models. In this multi-institutional retrospective cohort study, we identified NSCLC-BM patients treated with PD-1/PD-L1 inhibitors after local BM treatment (radiotherapy or neurosurgery) but before intracranial progression. Cox proportional hazards models were used to assess predictive value PD-L1 expression for overall survival (OS) and intracranial progression free survival (IC-PFS). Forty-eight BM patients with available PD-L1 expression were identified. PDL1 expression was positive in 33 patients (69%). Median survival was 26 months. In univariable analysis, PD-L1 predicted favorable OS (HR = 0.44; 95% CI 0.19 – 1.02; p = 0.055). This effect persisted after correcting for lung-graded prognostic assessment (lung-GPA) and other identified potential confounders (HR = 0.24; 95% CI = 0.10 – 0.61; p = 0.002). Moreover, when modeled as a continuous variable, there appeared to be a proportional relationship between percentage of PD-L1 expression and survival (HR = 0.86 per 10% expression, 95% CI 0.77 – 0.98, p = 0.02). In contrast, PD-L1 expression did not predict IC-PFS in uni- or multivariable analysis (adjusted HR = 0.54, 95% CI 0.26 – 1.14, p = 0.11). In patients with NSCLC-BMs treated with PD-1/PD-L1 checkpoint inhibitors and local treatment, PD-L1 expression may predict OS independent of lungGPA. IC-PFS did not show association with PD-L1 expression, although the present analysis may lack power to assess this. Larger studies are required to validate these findings.

Human Natural Killer (NK) Cells – From Development to Effector Functions

Natural Killer (NK) cells are the major lymphocyte subset of the innate immune system that mediate anti-viral and anti-tumor responses. It is well established that they develop mechanisms to distinguish self from non-self, during the process of NK cell education. Unlike T and B cells, NK cells lack clonotypic receptors and get activated after recognizing their target via germline-encoded receptors through natural cytotoxicity, cytokine stimulation, and antibody-dependent cellular cytotoxicity. Subsequently, they utilize cytotoxic granules, death receptor ligands, and cytokines to perform their effector functions. In this review, we provide an overview of NK cells ranging from development to effector functions, including the latest findings in the field. Funding Statement: None to declare. Declaration of Interests: The author does not have conflicts of interest to disclose.

Cancer-Associated Fibroblasts-Derived Exosomes Suppress Immune Cell Function in Breast Cancer via the miR-92/PD-L1 Pathway.

Cancer-associated fibroblasts (CAFs) are an essential component in the tumor microenvironment and have been reported to contribute to tumor progression through many mechanisms; however, the detailed mechanism underlying the immune-suppression effect of CAFs is not clearly defined. In this study, human breast cancer-derived CAFs were cultured, and CAF-derived exosomes in a culture medium were isolated. Using a miRNA profiles assay, we identify a significantly higher level of microRNA-92 isolated in CAFs exosomes. After treatment by CAF-derived exosomes, breast cancer cells express higher programmed cell death receptor ligand 1 (PD-L1), accompanied with increased miR-92 expression. Increased PD-L1 expression, which was induced by CAF-derived exosomes, significantly promotes apoptosis and impaired proliferation of T cells. The underlying mechanism of this effect was studied, proliferation and migration of breast cancer cells were increased after the transfection of miR-92, LATS2 was recognized as a target gene of miR-92, and further confirmed by a luciferase assay. Immunoprecipitation showed that LATS2 can interact with YAP1, chromatin immunoprecipitation confirmed that after nuclear translocation YAP1 could bind to the enhancer region of PD-L1 to promotes transcription activity. Furthermore, the animal study confirmed that CAFs significantly promoted tumor progression and impaired the function of tumor-infiltrated immune cells in vivo. Our data revealed a novel mechanism that can induce immune suppression in the tumor microenvironment.

Research on the effect of PD-L1 overexpression on CLL-1 CAR-T anti-acute myeloid leukemia

目的探讨程序性死亡受体配体1（PD-L1）对CLL-1 CAR-T细胞抗急性髓系白血病（AML）作用的影响。方法通过构建PD-L1表达载体、制备慢病毒、转导、单克隆筛选技术获得稳定表达PD-L1的THP-1单克隆细胞株（THP1-PDL1），然后以前期制备的CLL-1 CAR-T细胞为效应细胞，以THP-1、THP1-PDL1单克隆细胞株作为靶细胞，分别通过LDH检测、CBA法、CFSE法评价PD-L1过表达对CLL-1 CAR-T细胞裂解功能、炎性因子释放、细胞增殖等功能的影响。结果①成功制备了PD-L1慢病毒，并筛选获得了稳定表达PD-L1的THP1-PDL1单克隆细胞株，流式细胞术及PCR验证成功。②PD-L1过表达抑制了CLL-1 CAR-T细胞裂解THP-1细胞的能力；效靶比为10∶1时，CLL-1CAR-T细胞对THP1-PDL1细胞的杀伤效率明显低于对THP-1细胞的杀伤效率［（15.70±9.90）％对（51.95±2.52）％，P<0.05］。③PD-L1过表达减弱了CLL-1 CAR-T细胞释放细胞因子的能力［与THP1-PDL1细胞共培养时对与THP-1细胞共培养时：IFN-γ（115.66±3.13）pg/ml对（1708.16±26.76）pg/ml，P<0.05；IL-6（17.37±0.72）pg/ml对（124.92±4.26）pg/ml，P<0.05；IL-10（5.69±0.13）pg/ml对（124.12±3.02）pg/ml，P<0.05］；同时抑制了CLL-1 CAR-T细胞的增殖能力。结论成功构建了表达PD-L1的THP1-PDL1单克隆细胞株，同时证实了PD-L1过表达对CLL-1 CAR-T细胞抗AML的不利的影响，为通过PD-1/PD-L1通路调控CLL-1 CAR-T细胞功能提供了一定的理论基础。

Perioperative immunotherapy in muscle-invasive bladder cancer.

Muscle-invasive bladder cancer (MIBC) and non-muscle-invasive bladder cancer (NMIBC) are both major causes of morbidity and mortality. At diagnosis, MIBC is more likely to metastasize, but can often be treated with aggressive care. Standard treatment for MIBC patients is radical cystectomy but a select group of these individuals are not candidates for or will decline this treatment. Thus, bladder preservation therapy followed by combined chemoradiation may be considered. Despite the primary surgical management of MIBC, up to half of patients will obtain tumors at distant sites in the end and perioperative platinum-based chemotherapy comprises the standard of care. However, despite these aggressive treatment options, survival is poor and therefore, it is essential to combine local and systemic therapies. Therapeutic modalities contained cancer vaccines, immune checkpoint inhibitors and immunogenic therapy are emerging as alternatives to immunotherapy, and several drugs have recently been approved by the FDA. Currently, several trials of adjuvant immunotherapy based on checkpoint inhibitors that as monotherapy, inhibit the reaction between programmed death-receptor 1 (PD-1) and programmed death-receptor ligand 1 (PD-L1). Or combined therapies mixed with chemotherapy, radiation, or various immunotherapy are ongoing. This review summarizes the current state of immunotherapies and evolution of the chemotherapy landscape for MIBC perioperative treatment. Widespread research is currently being performed to investigate the role of perioperative immune checkpoint inhibition in both the neoadjuvant and adjuvant setting.