Programmed Cell Death Ligand 1 Antibody Research Articles

Prognostic Value of the Geriatric Nutritional Risk Index in Previously Untreated Patients with Advanced Non-Small Cell Lung Cancer Treated with a Combination Therapy of Anti-PD-1/-PD-L1 Antibodies and Platinum-Based Chemotherapy: A Multicenter Retrospective Study

Introduction: Combination therapy of anti-programmed cell death 1 (PD-1)/programmed cell death ligand 1 (PD-L1) antibodies and platinum-based chemotherapy has been widely used as a first-line treatment for patients with unresectable advanced non-small cell lung cancer (NSCLC) in clinical settings; however, prognostic biomarkers associated with survival outcomes have not been sufficiently investigated. Methods: We enrolled 147 previously untreated patients with advanced NSCLC who were treated with a combination therapy of anti-PD-1/-PD-L1 antibodies and platinum-based chemotherapy at eight institutions in Nagano Prefecture between December 2018 and April 2023. We evaluated the prognostic value of the geriatric nutritional risk index (GNRI), a systemic inflammatory nutritional biomarker calculated from body weight and serum albumin level, for patients with NSCLC treated with a combination therapy of anti-PD-1/-PD-L1 antibodies and platinum-based chemotherapy. Results: The cutoff value of the GNRI was set at 92. The high GNRI and low GNRI groups included 88 and 59 patients, respectively. The median follow-up period was 15.9 months. The overall survival (OS) in the high GNRI group was significantly longer than that in the low GNRI group (27.9 vs. 15.6 months, p = 0.015). Multivariate analysis revealed that a high GNRI was an independently favorable prognostic predictor for OS (hazard ratio, 1.73; 95% confidence interval, 1.06–2.86; p = 0.031). Conclusion: The present study demonstrates that the GNRI is a useful prognostic predictor in patients with NSCLC treated with a combination therapy of anti-PD-1/-PD-L1 antibodies and platinum-based chemotherapy in clinical settings.

Enabling continuous immune cell recirculation on a microfluidic array to study immunotherapeutic interactions in a recapitulated tumour microenvironment.

The effects of immunotherapeutics on interactions between immune and cancer cells are modulated by multiple components in the tumour microenvironment (TME), including endothelium and tumour stroma, which provide both a physical barrier and immunosuppressive stimuli. Herein, we report a recirculating chip to enable continuous immune cell recirculation through a microfluidic cell array to include these crucial players. This system consists of a three-layered cell array (μFCA) spatially emulating the TME, with tailored fluidic circuits establishing T cell recirculation. This platform enables the study of dynamics among the TME, immune cells in a circulatory system and cancer cell responses thereof. Through this system, we found that tumour endothelium hindered T cell infiltration into the reconstructed breast cancer tumour compartment. This negative effect was alleviated when treated with anti-human PD-L1 (programmed cell death ligand 1) antibody. Another key stromal component - cancer associated fibroblasts - attenuated T cell infiltration, compared against normal fibroblasts, and led to reduced apoptotic activity in cancer cells. These results confirm the capability of our tumour-on-a-chip system in identifying some key axes to target in overcoming barriers to immunotherapy by recapitulating immune cell interactions with the reconstructed TME. Our results also attest to the feasibility of scaling up this system for high-throughput cancer immunotherapeutic screening.

Evaluation of the predictive effect of PD-L1 expression on survival in early triple-negative breast cancer

Objectives: To find the prognostic factors related to early triple-negative breast cancer to optimize the therapeutic strategies, and explore the influence of programmed cell death ligand-1(PD-L1)expression in early triple-negative breast cancer on its prognosis, so as to provide support for clinical treatment decisions. Methods: Early triple-negative breast cancer patients treated at the National Cancer Center, National Clinical Research Center for Cancer, Cancer Hospital, Chinese Academy of Medical Sciences during 1st June, 2009 and 31st Oct, 2015 were enrolled in this study. All the clinicopathological data of patients were collected, and the paraffin sections of the surgical specimens were stained with estrogen receptor, progesterone receptor, human epidermal growth factor receptor-2, secreted protein acidic and rich in cysteine (SPARC), androgen receptor, PD-L1 and other antibodies by the immunohistochemical method. Kaplan-Meier survival and Cox regression curves were used for survival analysis of relevant clinical and pathological results and nomogram survival prediction models were established to explore the influence of relevant factors on the prognosis. Results: A total of 205 patients with triple-negative breast cancer were enrolled. Ninety patients (43.9%) were PD-L1 positive. The median follow-up time was 63 months. Thirty-seven patients were relapsed or recurrent and 16 patients were dead. The 5-year disease-free survival (DFS) rate and overall survival (OS) rate were 86.1% (95% CI: 81.4%-90.8%) and 93.6% (95% CI: 91.0%-97.6%), respectively, in the general population. Univariate Cox regression analysis showed that PD-L1 expression and lymph node metastasis were correlated with DFS and OS (P<0.05). In multivariate analysis, PD-L1 expression was an independent influencing factor of DFS, with PD-L1 positive patients possessing a significant survival benefit in DFS (HR=0.31, 95% CI: 0.13-0.73). Lymph node metastasis was an independent influencing factor of OS, and OS was significantly shortened in patients with positive lymph node metastasis (HR=3.24, 95% CI: 1.15-9.17). PD-L1, lymph node metastasis, menopausal status, Ki-67 index and adjuvant chemotherapy regimen were included to establish the 1- and 3-year DFS and OS nomogram prediction models, resulting in C indices of 0.698 and 0.748, respectively. Conclusions: PD-L1 expression is a predictive biomarker of good prognostic factor in triple-negative breast cancer patients. DFS is significantly prolonged in PD-L1 positive patients and OS also shows a prolongation trend. The nomogram prognosis prediction models have reference values for adjuvant chemotherapy in this patient group.

Dual-drug controllable co-assembly nanosystem for targeted and synergistic treatment of hepatocellular carcinoma

The effectiveness of chemotherapeutic agents for hepatocellular carcinoma (HCC) is unsatisfactory because of tumor heterogeneity, multidrug resistance, and poor target accumulation. Therefore, multimodality-treatment with accurate drug delivery has become increasingly popular. Herein, a cell penetrating peptide-aptamer dual modified-nanocomposite (USILA NPs) was successfully constructed by coating a cell penetrating peptide and aptamer onto the surface of sorafenib (Sora), ursolic acid (UA) and indocyanine green (ICG) condensed nanodrug (USI NPs) via one-pot assembly for targeted and synergistic HCC treatment. USILA NPs showed higher cellular uptake and cytotoxicity in HepG2 and H22 cells, with a high expression of epithelial cell adhesion molecule (EpCAM). Furthermore, these NPs caused more significant mitochondrial membrane potential reduction and cell apoptosis. These NPs could selectively accumulate at the tumor site of H22 tumor-bearing mice and were detected with the help of ICG fluorescence; moreover, they retarded tumor growth better than monotherapy. Thus, USILA NPs can realize the targeted delivery of dual drugs and the integration of diagnosis and treatment. Moreover, the effects were more significant after co-administration of iRGD peptide, a tumor-penetrating peptide with better penetration promoting ability or programmed cell death ligand 1 (PD-L1) antibody for the reversal of the immunosuppressive state in the tumor microenvironment. The tumor inhibition rates of USILA NPs + iRGD peptide or USILA NPs + PD-L1 antibody with good therapeutic safety were 72.38 % and 67.91 % compared with control, respectively. Overall, this composite nanosystem could act as a promising targeted tool and provide an effective intervention strategy for enhanced HCC synergistic treatment.

PDL1 immunohistochemistry in canine neoplasms: Validation of commercial antibodies, standardization of evaluation, and scoring systems.

Immuno-oncology research has brought to light the paradoxical role of immune cells in the induction and elimination of cancer. Programmed cell death protein 1 (PD1), expressed by tumor-infiltrating lymphocytes, and programmed cell death ligand 1 (PDL1), expressed by tumor cells, are immune checkpoint proteins that regulate the antitumor adaptive immune response. This study aimed to validate commercially available PDL1 antibodies in canine tissue and then, applying standardized methods and scoring systems used in human pathology, evaluate PDL1 immunopositivity in different types of canine tumors. To demonstrate cross-reactivity, a monoclonal antibody (22C3) and polyclonal antibody (cod. A1645) were tested by western blot. Cross-reactivity in canine tissue cell extracts was observed for both antibodies; however, the polyclonal antibody (cod. A1645) demonstrated higher signal specificity. Canine tumor histotypes were selected based on the human counterparts known to express PDL1. Immunohistochemistry was performed on 168 tumors with the polyclonal anti-PDL1 antibody. Only membranous labeling was considered positive. PDL1 labeling was detected both in neoplastic and infiltrating immune cells. The following tumors were immunopositive: melanomas (17 of 17; 100%), renal cell carcinomas (4 of 17; 24%), squamous cell carcinomas (3 of 17; 18%), lymphomas (2 of 14; 14%), urothelial carcinomas (2 of 18; 11%), pulmonary carcinomas (2 of 20; 10%), and mammary carcinomas (1 of 31; 3%). Gastric (0 of 10; 0%) and intestinal carcinomas (0 of 24; 0%) were negative. The findings of this study suggest that PDL1 is expressed in some canine tumors, with high prevalence in melanomas.

Development of novel peptide-based radiotracers for detecting PD-L1 expression and guiding cancer immunotherapy.

Due to tumor heterogeneity, immunohistochemistry (IHC) showed poor accuracy in detecting the expression of programmed cell death ligand-1 (PD-L1) in patients. Positron emission tomography (PET) imaging is considered as a non-invasive technique to detect PD-L1 expression at the molecular level visually, real-timely and quantitatively. This study aimed to develop novel peptide-based radiotracers [68Ga]/[18F]AlF-NOTA-IMB for accurately detecting the PD-L1 expression and guiding the cancer immunotherapy. NOTA-IMB was prepared by connecting 2,2'-(7-(2-((2,5-dioxopyrrolidin-1-yl)oxy)- 2-oxoethyl)-1,4,7-triazonane-1,4-diyl) diacetic acid (NOTA-NHS) with PD-L1-targeted peptide IMB, and further radiolabeled with 68Ga or 18F-AlF. In vitro binding assay was conducted to confirm the ability of [68Ga]/[18F]AlF-NOTA-IMB to detect the expression of PD-L1. In vivo PET imaging of [68Ga]NOTA-IMB and [18F]AlF-NOTA-IMB in different tumor-bearing mice was performed, and dynamic changes of PD-L1 expression level induced by immunotherapy were monitored. Radioautography, western blotting, immunofluorescence staining and biodistribution analysis were carried out to further evaluate the specificity of radiotracers and efficacy of PD-L1 antibody immunotherapy. [68Ga]NOTA-IMB and [18F]AlF-NOTA-IMB were both successfully prepared with high radiochemical yield (> 95% and > 60%, n = 5) and radiochemical purity (> 95% and > 98%, n = 5). Both tracers showed high affinity to human and murine PD-L1 with the dissociation constant (Kd) of 1.00 ± 0.16/1.09 ± 0.21nM (A375-hPD-L1, n = 3) and 1.56 ± 0.58/1.21 ± 0.39nM (MC38, n = 3), respectively. In vitro cell uptake assay revealed that both tracers can specifically bind to PD-L1 positive cancer cells A375-hPD-L1 and MC38 (5.45 ± 0.33/3.65 ± 0.15%AD and 5.87 ± 0.27/2.78 ± 0.08%AD at 120min, n = 3). In vivo PET imaging and biodistribution analysis showed that the tracer [68Ga]NOTA-IMB and [18F]AlF-NOTA-IMB had high accumulation in A375-hPD-L1 and MC38 tumors, but low uptake in A375 tumor. Treatment of Atezolizumab induced dynamic changes of PD-L1 expression in MC38 tumor-bearing mice, and the tumor uptake of [68Ga]NOTA-IMB decreased from 3.30 ± 0.29%ID/mL to 1.58 ± 0.29%ID/mL (n = 3, P = 0.026) after five treatments. Similarly, the tumor uptake of [18F]AlF-NOTA-IMB decreased from 3.27 ± 0.63%ID/mL to 0.89 ± 0.18%ID/mL (n = 3, P = 0.0004) after five treatments. However, no significant difference was observed in the tumor uptake before and after PBS treatment. Biodistribution, radioautography, western blotting and immunofluorescence staining analysis further demonstrated that the expression level of PD-L1 in tumor-bearing mice treated with Atezolizumab significantly reduced about 3 times and correlated well with the PET imaging results. [68Ga]NOTA-IMB and [18F]AlF-NOTA-IMB were successfully prepared for PET imaging the PD-L1 expression noninvasively and quantitatively. Dynamic changes of PD-L1 expression caused by immunotherapy can be sensitively detected by both tracers. Hence, the peptide-based radiotracers [68Ga]NOTA-IMB and [18F]AlF-NOTA-IMB can be applied for accurately detecting the PD-L1 expression in different tumors and monitoring the efficacy of immunotherapy.

Prognostic Significance of Programmed Cell Death Ligand 1 Expression in High-Grade Serous Ovarian Carcinoma: A Systematic Review and Meta-Analysis.

(1) Background: High-grade serous ovarian carcinoma (HGSOC) is an aggressive subtype of ovarian cancer. Recent advances have introduced prognostic markers and targeted therapies. Programmed cell death ligand 1 (PD-L1) has emerged as a potential biomarker for HGSOC, with implications for prognosis and targeted therapy eligibility; (2) Methods: A literature search was conducted on major databases, and extracted data were categorized and pooled. Subgroup analysis was performed for studies with high heterogeneity. (3) Results: Data from 18 eligible studies were categorized and pooled based on PD-L1 scoring methods, survival analysis types, and endpoints. The result showed an association between high PD-L1 expression and a favorable prognosis in progression-free survival (HR = 0.53, 95% CI = 0.35-0.78, p = 0.0015). Subgroup analyses showed similar associations in subgroups of neoadjuvant chemotherapy patients (HR = 0.6, 95% CI = 0.4-0.88, p = 0.009) and European studies (HR = 0.59, 95% CI = 0.42-0.82, p = 0.0017). In addition, subgroup analyses using data from studies using FDA-approved PD-L1 antibodies suggested a significant association between favorable prognosis and high PD-L1 expression in a subgroup including high and low stage data in overall survival data (HR = 0.46, 95% CI = 0.3-0.73, p = 0.0009). (4) Conclusions: This meta-analysis revealed a potential association between high PD-L1 expression and favorable prognosis. However, caution is warranted due to several limitations. Validation via large-scale studies, with mRNA analysis, whole tissue sections, and assessments using FDA-approved antibodies is needed.

Synchronous targeted delivery of TGF-β siRNA to stromal and tumor cells elicits robust antitumor immunity against triple-negative breast cancer by comprehensively remodeling the tumor microenvironment

The poor permeability of therapeutic drugs, limited T-cell infiltration, and strong immunosuppressive tumor microenvironment of triple-negative breast cancer (TNBC) acts as a prominent barrier to the delivery of drugs and immunotherapy including programmed cell death ligand-1 antibody (anti-PD-L1). Transforming growth factor (TGF)-β, an important cytokine produced by cancer-associated fibroblasts (CAFs) and tumor cells contributes to the pathological vasculature, dense tumor stroma and strong immunosuppressive tumor microenvironment (TME). Herein, a nanomedicine platform (HA-LSL/siTGF-β) employing dual-targeting, alongside hyaluronidase (HAase) and glutathione (GSH) triggered release was elaborately constructed to efficiently deliver TGF-β small interference RNA (siTGF-β). It was determined that this system was able to improve the efficacy of anti-PD-L1. The siTGF-β nanosystem efficiently silenced TGF-β-related signaling pathways in both activated NIH 3T3 cells and 4T1 cells in vitro and in vivo. This occurred firstly, through CD44-mediated uptake, followed by rapid escape mediated by HAase in endo/lysosomes and release of siRNA mediated by high GSH concentrations in the cytoplasm. By simultaneous silencing of TGF-β in stromal and tumor cells, HA-LSL/siTGF-β dramatically reduced stroma deposition, promoted the penetration of nanomedicines for deep remodeling of the TME, improved oxygenation, T cells infiltration and subsequent anti-PD-L1 deep penetration. The double suppression of TGF-β has been demonstrated to promote blood vessel normalization, inhibit an epithelial-to-mesenchymal transition (EMT), and further modify the immunosuppressive TME, which was supported by an overall increase in the proportion of dendritic cells and cytotoxic T cells. Further, a reduction in the proportion of immunosuppression cells such as regulatory T cells and myeloid-derived suppressor cells was also observed in the TME. Based on the comprehensive remodeling of the tumor microenvironment by this nanosystem, subsequent anti-PD-L1 therapy elicited robust antitumor immunity. Specifically, this system was able to suppress the growth of both primary and distant tumor while preventing tumor metastasis to the lung. Therefore, the combination of the dual-targeted siTGF-β nanosystem, alongside anti-PD-L1 may serve as a novel method to enhance antitumor immunotherapy against stroma-rich TNBC.

Immune-independent acquired resistance to PD-L1 antibody initiated by PD-L1 upregulation via PI3K/AKT signaling can be reversed by anlotinib.

Despite the benefit with cancer immunotherapies in clinical implication, immunotherapeutic resistance occurred in many patients and the mechanism remains unknown. Increasing evidence has revealed that cell-intrinsic programmed cell death ligand 1 (PD-L1) may play a non-negotiable part in immunotherapeutic resistance. Our present study aimed to elucidate the immune-independent acquired resistance mechanism to PD-L1 antibody. We found elevated PD-L1 expression induced by PD-L1 antibodies in cancer cell and vascular endothelial cells (VECs) with substantially acquired resistance to PD-L1 antibodies. Moreover, proliferation of resistant cells was accelerated and the apoptosis was reduced in the absence of immune compared with parental cells. Subsequently, we confirmed that the activation of the PI3K/AKT pathway is involved in the upregulation of PD-L1 expression. Finally, we found that low dose of anlotinib downregulated PD-L1 expression only in VECs via inhibiting the PI3K/AKT pathway; however, the same effect was not observed in cancer cells. To sum up, our findings revealed that upregulation of PD-L1 via activation of the PI3K/AKT signal pathway may promote acquired resistance to PD-L1 antibodies in an immune-independent manner. SIGNIFICANCE: These findings provide new mechanisms of immunotherapeutic resistance and effective evidence of anlotinib combined with immunotherapy.

Programmed cell death ligand-1 (PD-L1) expression in desmoid tumors: a retrospective study.

Desmoid tumor is a rare benign but locally aggressive monoclonal and fibroblastic proliferation. It lacks metastatic potential but is associated with a high local recurrence after surgery. It is either characterized by the Beta-catenin gene (CTNNB1) or the adenomatous polyposis coli gene (APC) mutation. The most appropriate treatment approach is watchful waiting with periodic follow-ups for asymptomatic patients. However, symptomatic patients who are not good candidates for surgery due to high morbidity risk may benefit from medical therapy. The new drugs targeting programmed cell death protein 1 (PD-1) and programmed death-ligand 1 (PD-L1) display promising results in many cancer types. This study assessed the PD-L1 status of desmoid tumors in 18 patients.Biopsy and resection materials of 18 patients diagnosed with desmoid tumors between April 2016 and April 2021 were retrieved and assessed for PD-L1 expression. The prepared slides were immunohistochemically stained with PD-L1 antibody using Leica Bond® automated immunohistochemistry stainer.No positive PD-L1 staining of the desmoid tumor cells was detected in any specimens. Intratumoral lymphocytes were present in all specimens. However, five of them were positively stained for PD-L1.Based on the results of our study, anti-PD-1/PD-L1 therapy may not be a valuable option in desmoid tumor treatment due to the lack of expression of PD-L1 by desmoid tumor cells. Nevertheless, the presence of positively stained intratumoral lymphocytes may warrant further studies.

Gold nanorods with iron oxide dual-modal bioprobes in SERS-MRI enable accurate programmed cell death ligand-1 expression detection in triple-negative breast cancer.

The efficiency of immunotherapy for triple-negative breast cancer (TNBC) is relatively low due to the difficulty in accurately detecting immune checkpoints. The detection of TNBC-related programmed cell death ligand-1 (PD-L1) expression is important to guide immunotherapy and improve treatment efficiency. Surface-enhanced Raman spectroscopy (SERS) and magnetic resonance (MR) imaging exhibit great potential for early TNBC diagnosis. SERS, an optical imaging mode, has the advantages of high detection sensitivity, good spatial resolution, and "fingerprint" spectral characteristics; however, the shallow detection penetration of SERS bioprobes limits its application in vivo. MR has the advantages of allowing deep penetration with no radiation; however, its spatial resolution needs to be improved. SERS and MR have complementary imaging features for tumor marker detection. In this study, gold nanorod and ultrasmall iron oxide nanoparticle composites were developed as dual-modal bioprobes for SERS-MRI to detect PD-L1 expression. Anti-PD-L1 (aPD-L1) was utilized to improve the targeting ability and specificity of PD-L1 expression detection. TNBC cells expressing PD-L1 were accurately detected via the SERS imaging mode in vitro, which can image at the single-cell level. In addition, bioprobe accumulation in PD-L1 expression-related tumor-bearing mice was simply and dynamically monitored and analyzed in vivo using MR and SERS. To the best of our knowledge, this is the first time a SERS-MRI dual-modal bioprobe combined with a PD-L1 antibody has been successfully used to detect PD-L1 expression in TNBC. This work paves the way for the design of high-performance bioprobe-based contrast agents for the clinical immunotherapy of TNBC.

Impact of Decalcification, Cold Ischemia, and Deglycosylation on Performance of Programmed Cell Death Ligand-1 Antibodies With Different Binding Epitopes: Comparison of 7 Clones

Programmed cell death ligand-1 (PD-L1) expression levels in patients’ tumors have demonstrated clinical utility across many cancer types and are used to determine treatment eligibility. Several independently developed PD-L1 immunohistochemical (IHC) predictive assays are commercially available and have demonstrated different levels of staining between assays, generating interest in understanding the similarities and differences between assays. Previously, we identified epitopes in the internal and external domains of PD-L1, bound by antibodies in routine clinical use (SP263, SP142, 22C3, and 28-8). Variance in performance of assays utilizing these antibodies, observed following exposure to preanalytical factors such as decalcification, cold ischemia, and duration of fixation, encouraged additional investigation of antibody-binding sites, to understand whether binding site structures/conformations contribute to differential PD-L1 IHC assay staining. We proceeded to further investigate the epitopes on PD-L1 bound by these antibodies, alongside the major clones utilized in laboratory-developed tests (E1L3N, QR1, and 73-10). Characterization of QR1 and 73-10 clones demonstrated that both bind the PD-L1 C-terminal internal domain, similar to SP263/SP142. Our results also demonstrate that under suboptimal decalcification or fixation conditions, the performance of internal domain antibodies is less detrimentally affected than that of external domain antibodies 22C3/28-8. Furthermore, we show that the binding sites of external domain antibodies are susceptible to deglycosylation and conformational structural changes, which directly result in IHC staining reduction or loss. The binding sites of internal domain antibodies were unaffected by deglycosylation or conformational structural change. This study demonstrates that the location and conformation of binding sites, recognized by antibodies employed in PD-L1 diagnostic assays, differ significantly and exhibit differing degrees of robustness. These findings should reinforce the need for vigilance when performing clinical testing with different PD-L1 IHC assays, particularly in the control of cold ischemia and the selection of fixation and decalcification conditions.

Dual TLR9 and PD-L1 targeting unleashes dendritic cells to induce durable antitumor immunity

BackgroundAlthough immune checkpoint inhibitors have been a breakthrough in clinical oncology, these therapies fail to produce durable responses in a significant fraction of patients. This lack of long-term efficacy may...

Dipeptidyl peptidase 4 inhibitor reduces tumor-associated macrophages and enhances anti-PD-L1-mediated tumor suppression in non-small cell lung cancer

PurposeThe efficacy of immune checkpoint inhibitors such as programmed cell death ligand 1 (PD-L1) antibodies in non-small cell lung cancer (NSCLC) is limited, and combined use with other therapies is recommended. Dipeptidyl peptidase 4 (DPP4) inhibitors, a class of small molecule inhibitors, are highly effective for treating type 2 diabetes. Emerging evidence implicates DPP4 inhibitors as immunomodulators that modify aspects of innate and adaptive immunity. We evaluated the combination of a DPP4 inhibitor (anagliptin) and PD-L1 blockade in an NSCLC mouse model.MethodsThe effect of the combination of anti-PD-L1 and anagliptin was evaluated in subcutaneous mouse models of NSCLC. Tumor-infiltrating immune cells were analyzed by flow cytometry. Bone marrow-derived monocytes of C57BL/6 mice were isolated in vitro to examine the underlying mechanism of anagliptin on the differentiation and polarization of macrophage.ResultsAnagliptin dramatically improved the efficacy of PD-L1 antibody monotherapy by inhibiting macrophage formation and M2 polarization in the tumor microenvironment. Mechanistically, anagliptin suppressed the production of reactive oxygen species in bone marrow monocytes by inhibiting NOX1 and NOX2 expression induced by macrophage colony-stimulating factor, reduced late ERK signaling pathway activation, and inhibited monocyte-macrophage differentiation. However, the inhibitory effect was reactivated by lipopolysaccharide and interferon-gamma interacting with corresponding receptors during M1 macrophage polarization, but not M2.ConclusionsAnagliptin can enhance PD-L1 blockade efficacy in NSCLC by inhibiting macrophage differentiation and M2 macrophage polarization, and combination therapy may be a promising strategy for treating PD-L1 blockade therapy-resistant patients with NSCLC.

Abstract 2180: The PD-L1 protein expression in Chinese patients with advanced esophageal cancers: a multi-center retrospective study

Abstract Introduction: Programmed cell death ligand-1 (PD-L1) is the ligand of programmed cell death-1 (PD-1), a member of the immunoglobulin gene superfamily that plays a role in programmed cell death. Accumulating evidence of anti-PD-1 therapy has showed improved survival benefit for esophageal cancer (EC) patients. PD-L1 has emerged as a crucial predictor for efficacy of immunotherapy. However, the understanding of PD-L1 as a biomarker is complicated by various immunohistochemistry platforms, PD-L1 antibodies, scoring systems, and cut-offs for immunotherapy. Although PD-L1 expression has been widely investigated, the real-world PD-L1 expression status in Chinese patients with advanced EC nationwide with unified testing platform, antibody, scoring system and cut-off is largely unrevealed. Methods: The present study was a nationwide multi-center retrospective analysis of data from six centers in China from August 9, 2021, to February 28, 2022. Patients with histologically or cytologically confirmed diagnoses of advanced EC were included. The primary outcome was the prevalence of high PD-L1 expression in patients with advanced EC. Immunohistochemical analysis of PD-L1 expression was performed by using the PD-L1 IHC 22C3 pharmDx assay in EC specimens. PD-L1 protein expression was assessed by using a combined positive score (CPS). The CPS≥ 10 was defined as a high PD-L1 high expression. The Chi-square test, Fisher’s exact test, or Wilcoxon rank sum test was used to compare the PD-L1 prevalence across demographic, clinicopathologic parameters, treatment status and other biomarkers. Results: Out of 488 enrolled patients with advanced EC, 482 patients were included in the final analysis. For all testing EC patients, 207 patients (42.9% [95% CI 38.48-47.50]) were PD-L1 high expression (CPS≥10). Between the PD-L1 high (CPS≥10) group and PD-L1 low (CPS&amp;lt;10) group, there were statistically significant differences in gender (P=0.046), alcohol consumption (P = 0.011), distant metastatic lesion number of patients with stage IV (P = 0.032), surgery (P = 0.012), systemic therapy (P = 0.004), and chemotherapy (P=0.004). Conclusion: In summary, the prevalence of high PD-L1 expression (CPS≥10) in Chinese patients with advanced EC in real-world setting using 22C3 assay is consistent with previous data in global clinical trials. Our findings of the related clinicopathological and treatment features to the PD-L1 expression can provide supplementary information for decision-making of immunotherapy and facilitate the better understanding of mechanism underlying PD-L1 and anti-tumor immunity. Citation Format: Liyan Xue, Jiaqi Wang, Dong Kuang, Jingping Yun, Yuan Li, Lili Jiang, Daoyuan Wu, Pei Duan, Shixun Lu, Yan Jin, Du He, Jing Qian, Wenmin Tang, Yan Wang, Jielin Li, Jianming Ying. The PD-L1 protein expression in Chinese patients with advanced esophageal cancers: a multi-center retrospective study [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 2180.

Abstract 6360: In vivo antitumor efficacy evaluation of ASC63, an oral small molecule PD-L1 inhibitor, in a humanized mouse tumor model

Abstract Background: ASC63 is an oral small molecule programmed cell death-ligand 1 (PD-L1) inhibitor. After oral dosing, ASC63 is rapidly absorbed and converted to its pharmacologically active metabolite ASC63-A in vivo. In vitro studies showed that ASC63-A could activate PD-L1 dimerization and internalization from cell membrane, thus interfere PD-1/PD-L1 interaction and enhance T-cell activation. Here we report the in vivo antitumor efficacy of ASC63 in a humanized mouse tumor model. Methods: 0.5×106 human PD-L1 knock in CT26 cells (CT26-hPD−L1) were implanted subcutaneously into BALB/c mice for tumor development. When the average tumor volume reached approximately 100 mm3, mice were randomly assigned (post-grouping, PG) and treated with vehicle, reference drug (10 mg/kg Atezolizumab intravenous injection twice a week [BIW]), 50 or 100 mg/kg ASC63 oral dosing twice a day (BID) for 18 days. Body weights and tumor volumes were measured regularly, and tumor growth inhibitions (TGI) of different groups were compared. TGI was calculated using the formula: TGI (%) =[1-(TRTV-1)/(CRTV-1)] ×100, where TRTV= mean relative tumor volume (RTV) of treatment group; CRTV= mean of control group. Results: At PG-D18, the tumor volume of vehicle group reached 1548 mm3, and Atezolizumab, 50 and 100 mg/kg AS63 groups showed TGI values of 35.17, 17.12 and 36.87%, respectively. Atezolizumab 10 mg/kg BIW and ASC63 100 mg/kg BID produced similar antitumor activities. One mouse in 100 mg/kg ASC63 group had body weight loss more than 10% at PG-D6, and was back to normal at PG-D9 after extra nutrition was provided, while the rest of mice showed a gradually increase in body weight during the study. No significant difference of body weight or body weight change was found among different groups of mice. Conclusion: Results of this study show that ASC63 is in general well tolerated in CT26-hPD−L1 humanized mouse tumor model, and ASC63 has comparable antitumor efficacy as the FDA-approved PD-L1 antibody, Atezolizumab. ASC63 is an oral small molecule PD-L1 inhibitor, and thus will have better patient compliance than injective PD-1/PD-L1 antibody. Results of this study support the continued investigation of ASC63. Citation Format: Jinzi J. Wu, Handan He. In vivo antitumor efficacy evaluation of ASC63, an oral small molecule PD-L1 inhibitor, in a humanized mouse tumor model [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 6360.

Total neoadjuvant treatment and PD-1/PD-L1 checkpoint inhibitor in locally advanced rectal cancer.

For local advanced rectal cancer (LARC), total neoadjuvant treatment (TNT) has shown more complete response (CR), reduced risk of distant metastasis (DM) and increase of the sphincter preservation rate. Now it is the one and only recommendation for high-risk group of LARC according to National Comprehensive Cancer Network (NCCN) rectal cancer guideline, while it is also preferentially recommended for low-risk group of LARC. TNT is also beneficial for distant rectal cancer patients who have need for organ preservation. Even though the prognostic value of programmed cell death-ligand 1 (PD-L1) in the neoadjuvant chemoradiotherapy (NACRT) of LARC patients is undetermined yet, the combination of NACRT and programmed cell death-1 (PD-1)/PD-L1 antibodies seem bring new hope for mismatch repair proficient (pMMR)/microsatellite stable (MSS) LARC patients. Accumulating small sample sized studies have shown that combining NACRT with PD-1/PD-L1 antibody yield better short-term outcomes for pMMR/MSS LARC patients than historic data. However, ideal total dose and fractionation of radiotherapy remains one of unresolved issues in this combination setting. Thorough understanding the impact of radiotherapy on the tumor microenvironment and their interaction is needed for in-depth understanding and exquisite design of treatments combination model.

Comparative evaluation of PD-L1 expression in cytology imprints, circulating tumour cells and tumour tissue in non-small cell lung cancer patients.

Alternative sources of tumour information need to be explored in patients with non-small cell lung cancer (NSCLC). Here, we compared programmed cell death ligand 1 (PD-L1) expression on cytology imprints and circulating tumour cells (CTCs) with PD-L1 tumour proportion score (TPS) from immunohistochemistry staining of tumour tissue from patients with NSCLC. We evaluated PD-L1 expression using a PD-L1 antibody (28-8) in representative cytology imprints, and tissue samples from the same tumour. We report good agreement rates on PD-L1 positivity (TPS ≥ 1%) and high PD-L1 expression (TPS ≥ 50%). Considering high PD-L1 expression, cytology imprints showed a PPV of 64% and a NPV of 85%. CTCs were detected in 40% of the patients and 80% of them were PD-L1+ . Seven patients with PD-L1 expression of < 1% in tissue samples or cytology imprints had PD-L1+ CTCs. The addition of PD-L1 expression in CTCs to cytology imprints markedly improved the prediction capacity for PD-L1 positivity. A combined analysis of cytological imprints and CTCs provides information on the tumoural PD-L1 status in NSCLC patients, which might be used when no tumor tissue is available.

4-1BB-Based CAR T Cells Effectively Reverse Exhaustion and Enhance the Anti-Tumor Immune Response through Autocrine PD-L1 scFv Antibody.

Exhaustion of chimeric antigen receptor (CAR) T cells is one of the limitations for CAR T efficacy in solid tumors and for tumor recurrence after initial CAR T treatment. Tumor treatment with a combination of programmed cell death receptor-1 (PD-1)/programmed cell death ligand-1 (PD-L1) blockage and CD28-based CAR T cells has been intensively studied. However, it remains largely unclear whether autocrine single-chain variable fragments (scFv) PD-L1 antibody can improve 4-1BB-based CAR T cell anti-tumor activity and revert CAR T cell exhaustion. Here, we studied T cells engineered with autocrine PD-L1 scFv and 4-1BB-containing CAR. The antitumor activity and exhaustion of CAR T cells were investigated in vitro and in a xenograft cancer model using NCG mice. CAR T cells with autocrine PD-L1 scFv antibody demonstrate enhanced anti-tumor activity in solid tumors and hematologic malignancies by blocking the PD-1/PD-L1 signaling. Importantly, we found that CAR T exhaustion was largely diminished by autocrine PD-L1 scFv antibody in vivo. As such, 4-1BB CAR T with autocrine PD-L1 scFv antibody combined the power of CAR T cells and the immune checkpoint inhibitor, thereby increasing the anti-tumor immune function and CAR T persistence, providing a cell therapy solution for a better clinical outcome.

Poređenje PD-L1 ekspresije u citološkom i histološkom materijalu seroznog high-grade karcinoma jajnika

Introduction: Neoplastic cells in peritoneal lavage express various proteins with significant prognostic and therapeutic potential. Such expression could differ from the expression in a primary tumor or in metastases. In this research, we compared PD-L1 (programmed cell death ligand-1) expression on ovarian cancer cells in cytological material with its expression on peritoneal metastases and a primary tumor. Materials and methods: The study included 30 patients who had been operated on for high-grade serous ovarian cancer (HGSC) in FIGO IIIC, over the period of one year. Cytoblocks, cytological and tissue microarrays were assembled and immunostained with PD-L1 antibody. For each tumor compartment we determined four PD-L1 expression categories: negative, low, moderate, and strong expression, according to the percentage of membrane positive tumor cells. Moderate and strong positivity together were considered as high PD-L1 expression. Results: Moderate PD-L1 expression was the most frequent pattern in primary HGSC (50%) and in peritoneal metastases (omentum) (60%). Cytological samples mostly showed low PD-L1 expression (57%). Statistical analysis did not show a significant difference in PD-L1 expression between the study groups. We found a positive correlation of PD-L1 expression between different, matched tumor samples in every patient, with statistical significance (p &lt; 0.05) between all the analyzed samples. Conclusion: PD-L1 expression was similar in all three tumor compartments. This could point to similar peritumor regulatory mechanisms of HGSC in primary tumor tissue and cytology tumor samples. Immunohistochemical analysis of the assembled cytoblocks is sufficiently reliable in the assessment of PD-L1 expression on cancer ovarian cells from cytological material.