Programmed Death-ligand 1 Antibody Research Articles

Targeting Nuclear Receptor Coactivator SRC-1 Prevents Colorectal Cancer Immune Escape by Reducing Transcription and Protein Stability of PD-L1.

Programmed death-ligand 1 (PD-L1) is overexpressed in multiple cancers and critical for their immune escape. It has previously shown that the nuclear coactivator SRC-1 promoted colorectal cancer (CRC) progression by enhancing CRC cell viability, yet its role in CRC immune escape is unclear. Here, we demonstrate that SRC-1 is positively correlated with PD-L1 in human CRC specimens. SRC-1 deficiency significantly inhibits PD-L1 expression in CRC cells and retards murine CRC growth in subcutaneous grafts by enhancing CRC immune escape via increasing tumor infiltration of CD8+ T cells. Genetic ablation of SRC-1 in mice also decreases PD-L1 expression in AOM/DSS-induced murine CRC. These results suggest that tumor-derived SRC-1 promotes CRC immune escape by enhancing PD-L1 expression. Mechanistically, SRC-1 activated JAK-STAT signaling by inhibiting SOCS1 expression and coactivated STAT3 and IRF1 to enhance PD-L1 transcription as well as stabilized PD-L1 protein by inhibiting proteasome-dependent degradation mediated by speckle type POZ protein (SPOP). Pharmacological inhibition of SRC-1 improved the antitumor effect of PD-L1 antibody in both subcutaneous graft and AOM/DSS-induced murine CRC models. Taken together, these findings highlight a crucial role of SRC-1 in regulating PD-L1 expression and targeting SRC-1 in combination with PD-L1 antibody immunotherapy may be an attractive strategy for CRC treatment.

Translate Pharmacokinetics of PD-1/PD-L1 Monoclonal Antibodies from Cynomolgus Monkey to Human: Comparison of Different Approaches

Antibodies blocking programmed death-1 (PD-1) and its natural ligand programmed death-ligand 1 (PD-L1) have been proved to be promising strategies in recent years. Hundreds of PD-1/PD-L1 antibodies are under development worldwide. Prediction of human pharmacokinetics (PK) in the preclinical stage is critical for designing dosing regimens in first-in-human studies. This study aims to predict the PK of PD-1/PD-L1 antibodies in human by scaling of monkey data. A systematic literature search of published articles on the PK of PD-1/PD-L1 antibodies in cynomolgus monkey and in human was conducted. Allometric scaling (AS), the species time-invariant (STIV) method, as well as physiologically based pharmacokinetic (PBPK) modeling were investigated. Six antibodies (avelumab, atezolizumab, nivolumab, pembrolizumab, cemiplimab, and zimberelimab) were included for investigation. The exponents used in this study were 0.85 and 1 for clearance (CL) and distribution volume (V), respectively, both for AS and STIV methods. The generic PBPK model for macromolecules in PK-Sim was used without further modifications. The dissociation constant of the antibody for binding to FcRn (KD) in endosome space for human was assumed to be two-fold of that for monkey. Predicted human CLs for the majority of drugs were within the observed range, while Vs were not well predicted using the AS method. The STIV method and the generic PBPK model can be employed to translate concentration-time curves of PD-1/PD-L1 antibodies from cynomolgus monkey to human with comparable efficacy. The results of this study provide reference for the early development of PD-1/PD-L1 antibodies.

Shedding Light on the Role of Exosomal PD-L1 (ExoPD-L1) in Cancer Progression: an Update.

Exosomes are the primary category of extracellular vesicles (EVs), which are lipid-bilayer vesicles with biological activity spontaneously secreted from either normal or tansformed cells. They serve a crucial role for intercellular communication and affect extracellular environment and the immune system. Tumor-derived exosomes (TEXs) enclose high levels of immunosuppressive proteins, including programmed death-ligand 1 (PD-L1). PD-L1 and its receptor PD-1 act as crucial immune checkpoint molecules, thus facilitating tumor advancement by inhibiting immune responses. PDL-1 is abundantly present on tumor cells and interacts with PD-1 on activated T cells, resulting in T cell suppression and allowing immune evasion of cancer cells. Various FDA-approved monoclonal antibodies inhibiting the PD-1/PD-L1 interaction are commonly used to treat a diverse range of tumors. Although the achieved results are significant, some individuals have a poor reaction to PD-1/PD-L1 blocking. PD-L1-enriched TEXs may mimic the impact of cell-surface PD-L1, consequently potentiating tumor resistance to PD1/PD-L1 based therapy. In light of this, a strong correlation between circulating exosomal PD-L1 levels and response rate to anti-PD-1/PD-L1 antibody treatment has been evinced. This article inspects the function of exosomal PDL-1 in developing resistance to anti-PD-1/PD-L1 therapy for opening new avenues for overcoming tumor resistance to such modalities and development of more favored combination therapy.

STAT3 Expression and Its Correlation with PD-L1 Expression in Non-Hodgkin's Lymphoma and Hodgkin's Lymphoma at Dr. Saiful Anwar Regional Public Hospital in Malang, Indonesian Population.

Lymphomas are malignant lymphocyte neoplasms that globally account for 10% of cancers in individuals aged <20 years. Malignant lymphomas are divided into Hodgkin's lymphoma (HL) and non-Hodgkin's lymphoma (NHL). Despite the availability of many therapeutic modalities for lymphoma, such as Brentuximab vedotin, Nivolumab, and Pembrolizumab, it is still necessary to identify appropriate strategies with minimal side effects. Immunotherapy is a promising approach, exemplified by targeting JAK/STAT3 signaling, which can inhibit tumor growth and enhance antitumor immune responses. Hence, STAT3 (signal transducer and activator of transcription 3) is a promising therapeutic target. PD-L1 (programmed death-ligand 1), an immune checkpoint molecule, is used as a frontline treatment for various cancers. This study aims to determine STAT3 expression and its correlation with PD-L1 expression in NHL and HL to serve as a basis for further research on anti-STAT3 and its combination with other therapy targets. Samples were obtained from paraffin blocks of patients with confirmed diagnoses of NHL and HL, and then immunohistochemical staining was carried out with PD-L1 and STAT3 antibodies. The collected data were then analyzed using SPSS. Among the 10 HL patients, no patients (0%) expressed STAT3, while nine patients (90%) expressed PD-L1. Among the 10 NHL patients, 1 patient (10%) expressed STAT3, while six patients (60%) expressed PD-L1. There were no significant differences in STAT3 expression and PD-L1 expression between HL patients and NHL patients. There was no correlation between STAT3 and PD-L1 expression in HL and NHL because almost all STAT3 expressions were negative. Although this study revealed no differences between STAT3 and PD-L1 expression in HL and NHL and no significant correlation between STAT3 and PD-L1 expression in HL and NHL, this may serve as the basis for understanding the role of STAT3 and PD-L1 in the regulation of HL and NHL, which may be useful for further research targeting STAT3 and PD-L1 immunotherapy in HL and NHL.

Efficacy and Safety of Anti–Programmed Cell Death Protein 1/Programmed Death-Ligand 1 Antibodies Plus Chemotherapy as First-Line Treatment for NSCLC in the People’s Republic of China: a Systematic Review and Meta-Analysis

IntroductionThe available approved anticancer drugs for Chinese patients are relatively limited because of China's low participation rate in international clinical trials. Therefore, a focus on approved anti–programmed cell death protein 1 (PD-1)/programmed death-ligand 1 (PD-L1) drugs in China is needed. This study aims to assess the heterogeneity of anti–PD-1/PD-L1 antibodies manufactured in China (domestic PD-1/PD-L1) and overseas (imported PD-1/PD-L1) when combined with chemotherapy as the first-line treatment of NSCLC. MethodsA systematic search was performed using PubMed, EMBASE, and Cochrane Library of publications up to July 13, 2023. Meta-analysis was applied to compare the efficacy and safety profile between anti–PD-1/PD-L1 antibodies plus chemotherapy (PD-1/PD-L1+Chemo) and chemotherapy alone using STATA software. Pooled hazard ratios for progression-free survival and overall survival, odds ratios for objective response rate, and incidence rate of grade greater than or equal to three treatment-related adverse events with 95% confidence intervals were calculated in the domestic group and imported group by a random-effects model, and the heterogeneity between the two estimates was assessed. ResultsThere were 14 eligible clinical studies with a total of 3951 patients involved in this analysis, including eight studies of domestic PD-1/PD-L1+Chemo and six studies of imported PD-1/PD-L1+Chemo. The study revealed that there was no significant difference between domestic and imported PD-1/PD-L1+Chemo in overall survival (p = 0.80), progression-free survival (p = 0.53), and incidence rate of grade greater than or equal to three treatment-related adverse events (p = 0.10). Nevertheless, the objective response rate of imported PD-1/PD-L1+Chemo was significantly higher than that of domestic PD-1/PD-L1+Chemo (p = 0.03). ConclusionsDomestic anti–PD-1/PD-L1 antibodies plus chemotherapy were found to have comparable efficacy and safety to those combined with imported anti–PD-1/PD-L1 antibodies based on current evidence.

Polymer-based antibody mimetics (iBodies) target human PD-L1 and function as a potent immune checkpoint blocker

Immune checkpoint blockade (ICB) using monoclonal antibodies against programmed cell death protein 1 (PD-1) or programmed death-ligand 1 (PD-L1) is the treatment of choice for cancer immunotherapy. However, low tissue permeability, immunogenicity, immune-related adverse effects, and high cost could be possibly improved using alternative approaches. On the other hand, synthetic low-molecular-weight (LMW) PD-1/PD-L1 blockers have failed to progress beyond in vitro studies, mostly due to low binding affinity or poor pharmacological characteristics resulting from their limited solubility and/or stability.Here, we report the development of polymer-based anti-human PD-L1 antibody mimetics (α-hPD-L1 iBodies) by attaching the macrocyclic peptide WL12 to a N-(2-hydroxypropyl)methacrylamide copolymer. We characterized the binding properties of iBodies using surface plasmon resonance, enzyme-linked immunosorbent assay, flow cytometry, confocal microscopy, and a cellular ICB model. We found that the α-hPD-L1 iBodies specifically target human PD-L1 (hPD-L1) and block the PD-1/PD-L1 interaction in vitro, comparable to the atezolizumab, durvalumab, and avelumab licensed monoclonal antibodies targeting PD-L1. Our findings suggest that iBodies can be used as experimental tools to target hPD-L1 and could serve as a platform to potentiate the therapeutic effect of hPD-L1-targeting small molecules by improving their affinity and pharmacokinetic properties.

PD-L1 Immunohistochemical Expression in Endometrial Carcinoma: Egyptian Cross-Sectional Study.

Endometrial carcinoma (EC) is the most common cancer of the female genital tract. According to the recently evolved strategies of cancer immunotherapy, immune checkpoints inhibitors are one of the most crucial strategies. Programmed Death Ligand 1 (PD-L1) is an important immune checkpoint regulator. PD-L1 antibodies have shown efficacy in clinical trials of some malignancies. Some of these antibodies have been approved for clinical usage by the Food and Drug Administration (FDA). This retrospective study included a total of 100 ECs, collected from archived, formalin-fixed, paraffin-embedded tissue blocks of hysterectomy specimens of Egyptian females. The samples were immunohistochemically analyzed for PD-L1 expression (in both tumor cells; TCs and tumor infiltrating leucocytes; TILs) by a semiquantitative score (0 to 4), with cutoff points of (0: <1% of the cells, 1: 1% to 4%, 2: 5% to 9%, 3: 10% to 49%, and 4: ≥ 50%). Membranous staining only was considered positive. PD-L1 was highly expressed in ECs (67% TCs+ and 61% TILs+), with statistically significant relationships with age, lympho-vascular space invasion (LVSI) and TILs score (P = 0.006, 0.016 and <0.005 respectively). However, no statistically significant relationships were detected between PD-L1 expression and the following parameters: histological type, histological grade, pathological stage (pT) or FIGO stage, myometrial, cervical, adnexal/serosal, parametrial involvements and nodal metastasis, as well as ESMO risk stratification system. Moreover, statistically significant relationships were achieved when correlating TILs score with tumor grade and LVSI (P = 0.034 and 0.012 respectively). Also, comparing endometrial hyperplasia (EH) PD-L1 and TCs PDL1 median scores achieved statistically significant relationship (P = 0.001). Our results concluded that PD-L1 expression was greater in both TCs and TILs in a subgroup of patients that have advanced age, LVSI and are TILs-rich, identifying them as potential candidates for anti-PD-1/PD-L1 immunotherapy.

GABA/baclofen stabilizes PD-L1 and enhances immunotherapy of breast cancer

The programmed death-ligand 1 (PD-L1) on the surface of tumor cells binds to the receptor programmed cell death protein 1 (PD-1) on effector T cells, thereby inhibiting the anti-tumor immune response. Immune checkpoint blockade (ICB) therapy targeting PD-1/PD-L1 has been approved for the treatment of human cancers with lasting clinical benefit. However, many cancer patients did not respond to anti-PD-1/PD-L1 antibody blocking therapy or drugs targeting PD-1/PD-L1. Recent studies have shown that the response to PD-1/PD-L1 blockade may be related to the PD-L1 abundance of tumor cells. Therefore, it is of crucial significance to find drugs to regulate the expression of PD-L1, which can provide new strategies to improve the response rate and efficacy of PD-1/PD-L1 blocking in cancer treatment. Here, we found that GABA and baclofen, upregulates the protein level of PD-L1 by reducing the mRNA and protein levels of STUB1, a E3 ubiquitin ligase, thereby decreasing the interaction between STUB1 and PD-L1, and ultimately stabilizing PD-L1. Notably, GABA and baclofen did not affect cell proliferation in vitro, while in the treatment of breast cancer in mice, the therapeutic effect of baclofen combined with anti-PD-L1 antibody is significantly better than that of using anti-PD-L1 antibody alone by stimulating tumor infiltration of CD8+ T cells and antitumor immunity. Taken together, we unveiled a previously unappreciated role of GABA/baclofen in stabilizing PD-L1 and enhancing the immunotherapy of breast cancer.

Correlation between estrogen receptor and programmed death ligand-1 in type I endometrial cancer

ObjectiveTo determine the effect of estrogen receptor (ER) on programmed death-ligand 1 (PD-L1) expression in type I endometrial cancer (EC). Material and MethodsThis retrospective study included 85 patients with type I EC who underwent surgery at Dr. Soetomo Hospital between 2018 and 2022. A random sampling technique was employed. Immunohistochemistry (IHC) with ER and PD-L1 antibodies was performed on all samples. In this study, ER expression served as the independent variable, while PD-L1 expression was considered the dependent variable. Data analysis was performed using Spearman's rank correlation coefficient test. ResultsOut of the 85 patients with type I EC, 58 (68.2%) exhibited positive and 27 (31.8%) exhibited negative ER expression. Meanwhile positive PD-L1 expression was seen in 67 (78.8%) and 18 (21.2%) exhibited negative PD-L1 expression. The study revealed a strong negative correlation between ER and PD-L1 expression in EC (rho value = −0.886, p-value = 0.0001). ConclusionER downregulates PD-L1 in type I EC. The findings of this study can be used as reference data and as the basis for further research, especially investigations of the prognostic and immunotherapeutic value of ER and PD-L1 expression in type I EC.

A Hybrid Nanoadjuvant Simultaneously Depresses PD-L1/TGF-β1 and Activates cGAS-STING Pathway to Overcome Radio-Immunotherapy Resistance.

Currently, certain cancer patients exhibit resistance to radiotherapy due to reduced DNA damage under hypoxic conditions and acquired immune tolerance triggered by transforming growth factor-β1 (TGF-β1) and membrane-localized programmed death ligand-1 (PD-L1). Meanwhile, cytoplasm-distributed PD-L1 induces radiotherapy resistance through accelerating DNA damage repair (DDR). However, the disability of clinically used PD-L1 antibodies in inhibiting cytoplasm-distributed PD-L1 limits their effectiveness. Therefore, a nanoadjuvant is developed to sensitize cancer to radiotherapy via multi-level immunity activation through depressing PD-L1 and TGF-β1 by triphenylphosphine-derived metformin, and activating the cGAS-STING pathway by generating Mn2+ from MnO2 and producing more dsDNA via reversing tumor hypoxia and impairing DDR. Thus, Tpp-Met@MnO2@Alb effectively enhances the efficiency of radiotherapy to inhibit the progression of irradiated local and abscopal tumors and tumor lung metastases, offering a long-term memory of antitumor immunity without discernible side effects. Overall, Tpp-Met@MnO2@Alb has the potential to be clinically applied for overcoming radio-immunotherapy resistance.

PD-L1 immunohistochemical expression in bladder urothelial cancer with SP263, SP142 and 22C3 antibodies: A comparative study

Programmed death ligand 1 (PD-L1) is currently the only biomarker used for the selection of patients with bladder urothelial cancer for immunotherapy. Several platforms, antibodies and scores are currently available for the evaluation of the expression of PD-L1 in immunohistochemistry (IHC). In this study three different antibodies (SP263, SP142 and 22C3) were compared to establish their performances and concordance rates. Twenty-four consecutive cases of surgically resected urothelial cancers of the bladder were enrolled. All cases were revised, and appropriate tumor areas were selected for IHC. Three commercially available PD-L1 antibodies were tested: 22C3 pharmDx with Dako Autostainer Link 48 (Dako, Carpinteria, Ca), and SP263 and SP142 with the Ventana BenchMark (Ventana Medical Systems, Tucson, AZ) platform. All slides were evaluated by an expert pathologist and both the tumor proportion score (TPS) and the combined positive score (CPS) were determined and compared at two different cut-off levels (≥ 1 and ≥ 10). The SP263 and 22C3 clones produced more positive results with the CPS and TPS scores, respectively. The CPS score identified more positive cases than the TPS score, irrespectively of the clone or the cut-off used; the difference was statistically significant in both the SP263 and SP142 clones with the ≥1 cut-off. No statistically significant differences were found between the clones when the ≥1 cut-off was used, irrespectively of the score. At the contrary, a statistically significant difference (p = 0.024) and a trend to significance (p = 0.082) were respectively found for the TPS and CPS scores, when the SP22C3 and the SP142 clones were compared at a cut-off level of ≥10. The ICC test using CPS was 0.676 and 0.578 for the ≥1 and ≥ 10 cut-offs respectively, and 0.729 and 0.467 respectively for the same cut-offs using TPS. This suggests that the three antibodies under investigation cannot be used interchangeably, especially the 22C3 and SP142 clones which showed statistically significant difference when TPS was tested at a ≥ 10 cut-off.

Correlation between PD-L1 and Ki-67 Expression at various T-stage Clear Cell Renal Cell Carcinomas

Renal cell carcinoma (RCC) is a malignant neoplasm originating from renal epithelium, with the clear cell renal cell carcinoma (ccRCC)being the most common type (80%) and the most common cause of death among other types of kidney cancer. Pathological stage is an important parameter that affects ccRCC survival, followed by nuclear grade. Pathological staging of RCC according to the AJCC (American Joint Committee on Cancer) TNM system 8th edition is based on local extension of the main tumor (T), involvement of lymph node (N), and metastasis (M). Ki-67 is a marker of proliferation used to assess tumor grade. High Ki-67 correlates with poor prognosis, advanced clinical and pathological features, thus Ki-67 can be used as a biomarker in the management of RCC.Ki-67 is routinely used to see the proliferation index in various cases of malignancy, but not in kidney malignancy. Programmed death ligand 1 (PD-L1) acts as a negative regulator of T cell-mediated anti-tumor immune responses. PD-L1 is expressed on T cells, B cells, macrophages, dendritic cells, endothelial cells and in various tumor cells including ccRCC. This study aims to determine the correlation between the expression of PD-L1 and Ki-67 in various T-stage clear cell renal cell carcinomas. Material and Method: This was an observational analytical study with cross-sectional approach toward 52 cases of ccRCC whose diagnosis was made histopathologically at the Anatomical Pathology Installation of Dr. Soetomo General Academic Hospital Surabaya from January 2014 to December 2020. Immunohistochemical stainingwas carried out using Ki-67 and PD-L1 antibodies, followed by an assessment using a scoring system. T-stage data were obtained from the patients’ medical recordswhich were then analyzed statistically with the Spearman test. Result: The study included 52 cases of ccRCC obtained from nephrectomy specimens at RSUD dr. Soetomo between 2014–2020. The age distribution of the subjects was 29–69 years and the mean and median age was 53 years. The ratio of male patients compared to female patients was 2.5:1. The majority was stage T2 (50%). Statistical test results showed no correlation between the expression of PD-L1 and Ki-67 in various T-stage clear cell renal cell carcinomas (p=0.965 and p=0.680). Conclusion: This study showed no correlation between the expression of PD-L1 and Ki-67 in various T-stage clear cell renal cell carcinomas. Nonetheless PD-L1 can be considered as an important biomarker with a poorer prognosis and aggressive clinicopathological findings in patients with RCC.

Elucidating the Role of Tolerogenic Dendritic Cells in Immune Tolerance and Disease Progression in Multiple Myeloma

Introduction: Previous research has demonstrated that programmed death-ligand 1 (PD-L1) in multiple myeloma (MM) cells not only suppresses anti-tumor immune responses but also enhances malignant potential through the PD-L1-PD-1 interaction [Ishibashi M, et al. Cancer Immunol Res. 2016]. However, it has not yet been shown that monotherapy and combination therapies utilizing PD-1/PD-L1 antibodies are sufficiently effective for MM. One reason for this is the absence of myeloma-specific cytotoxic T lymphocytes induction in the MM tumor microenvironment. In certain cancers, tumor-infiltrating dendritic cells (DCs) undergo conversion into tolerogenic DCs, which are crucial for inducing and maintaining T-cell tolerance, although this remains unclear in MM. Thus, this study aimed to investigate the function and induction mechanisms of tolerogenic DCs in the MM microenvironment. Materials and Methods: (1) Flow cytometry (FCM) was employed to assess the two conventional DC (cDC; lineage negative, HLA-DR +CD11c high) subsets, cDC1 (CD141 + cDC) and cDC2 (CD1c + cDC), in bone marrow (BM) samples obtained from MM patients (n=17) and healthy controls (n=13). (2) CD14 + monocytes were cultured with IL-4 and GM-CSF to generate monocyte-derived DCs (moDCs). Simultaneously, moDCs were co-cultured with MM cell lines using a trans-well system. The characteristics and functions of moDCs were analyzed using real-time PCR, RNA-sequencing (RNA-seq), western blotting, ELISA, and FCM after lipopolysaccharide stimulation. Results: The frequency of cDC1 subsets was significantly lower in MM patients compared to controls, while the major cDC2 subset did not differ. Similarly, when moDCs were co-cultured with MM cells, moDC numbers were markedly reduced. These co-cultured moDCs exhibited downregulated expression of activation markers CD80, CD86, and CD83, along with decreased phosphorylation of ERK and S6K. Conversely, these moDCs upregulated the expression of immunosuppressive factors IL-10, ARG1, and NOS2 through increased transcription factor C/EBPβ. Moreover, these moDCs inhibited T-cell proliferation, activation, and interferon-γ production in comparison to control moDCs, indicating the presence of immature and tolerogenic phenotypes. However, these phenotypes were not observed in moDCs co-cultured with soluble factors secreted from MM and stromal cells. Treatment with AZD3965 improved the phenotype of moDCs co-cultured with MM cells, reversing their suppressive effect on T-cell proliferation. AZD3965 targets monocarboxylate transporter 1 (MCT1) in MM cells, thereby suppressing extracellular lactate accumulation and acidic pH in the MM microenvironment. Furthermore, RNA-seq analysis comparing moDCs co-cultured with and without MM cells revealed downregulation of gene sets associated with activated DCs in moDCs co-cultured with MM. Notably, moDCs co-cultured with MM showed high enrichment of gene sets related to lysosome biogenesis and NOD-like receptor signaling. This suggests that inflammasome activation in these moDCs leads to caspase-1 activation, resulting in increased levels of mature IL-1β and IL-18 in their cell culture supernatants. Additionally, co-culturing CD38-positive MM cells with CD203a/CD73-positive HS-5 stromal cells and NAD + resulted in the generation of adenosine in the cell culture supernatant. Adenosine promotes the immaturation of mature DCs; however, inflammasome activation does not occur in these DCs. Conclusions: Patients with MM exhibit a reduced frequency of cDC1 subsets, which are crucial for cross-presentation to CD8 + T cells. moDCs in acid pH conditions derived from MM cells display an immature phenotype and impaired function due to decreased DC activation signals. Furthermore, inflammasome activation promotes the secretion of IL-1β and IL-18, contributing to pro-tumorigenic inflammation in the MM microenvironment. Moreover, adenosine generated via the CD38/CD203a/CD73 adenosinergic pathway promotes the immaturation and dysfunction of moDCs. Thus, the characteristics of tolerogenic DCs may vary depending on the MM microenvironment. These findings highlight the induction of tolerogenic DCs by the metabolic microenvironment in MM, leading to immune tolerance and disease progression.

A Polymeric Hydrogel to Eliminate Programmed Death-Ligand 1 for Enhanced Tumor Radio-Immunotherapy.

Programmed death-ligand 1 (PD-L1) is a specialized shield on tumor cells that evades the immune system. Even inhibited by PD-L1 antibodies, a cycling process constantly transports PD-L1 from inside to outside of cells, facilitating the renewal and replenishment of PD-L1 on the cancer cell membrane. Herein, we develop a sodium alginate hydrogel consisting of elesclomol-Cu and galactose to induce persistent cuproptosis, leading to the reduction of PD-L1 for radio-immunotherapy of colon tumors. First, a prefabricated hydrogel is synthesized by immobilizing elesclomol onto a sodium alginate saccharide chain through the coordination with bivalent copper ions (Cu2+), followed by incorporation of galactose. After implantation into the tumors, this prefabricated hydrogel can be further cross-linked in the presence of physiological calcium ions (Ca2+), resulting in the formation of a hydrogel with controlled release of elesclomol-Cu2+ (ES-Cu) and galactose. The hydrogel effectively induces the oligomerization of DLAT and cuproptosis in colorectal cancer cells. Interestingly, radiation-induced PD-L1 upregulation is abrogated in the presence of the hydrogel, releasing ES-Cu and galactose. Consequently, the sensitization of tumor to radiotherapy and immunotherapy is significantly improved, further prolonging the survival of tumor-bearing mice in both local and metastatic tumors. Our study introduces an approach that combines cuproptosis with immunotherapy and radiotherapy.

Ginsenoside Rh2 augmented anti-PD-L1 immunotherapy by reinvigorating CD8+ T cells via increasing intratumoral CXCL10

Profiting from the sustained clinical improvement and prolonged patient survival, immune checkpoint blockade of programmed cell death protein 1 (PD-1)/programmed death-ligand 1 (PD-L1) axis has emerged as a revolutionary cancer therapy approach. However, the anti-PD-1/PD-L1 antibodies only achieve a clinical response rate of approximately 20%. Herein, we identified a novel combination strategy that Chinese medicine ginseng-derived ginsenoside Rh2 (Rh2) markedly improved the anti-cancer efficacy of anti-PD-L1 antibody in mice bearing MC38 tumor. Rh2 combined with anti-PD-L1 antibody (combo treatment) further triggered the infiltration, proliferation and activation of CD8+ T cells in the tumor microenvironment (TME). Depletion of CD8+ T cells by mouse CD8 blocking antibody abolished the anti-cancer effect of combo treatment totally. Mechanistically, combo treatment further increased the expression of CXCL10 through activating TBK1-IRF3 signaling pathway, explaining the increased infiltration of T cells. Employing anti- CXC chemokine receptor 3 (CXCR3) blocking antibody prevented the T cells infiltration and abolished the anti-cancer effect of combo treatment. Meanwhile, combo treatment increased the percentage of M1-like macrophages and raised the ratio of M1/M2 macrophages in TME. By comparing the anti-cancer effect of combo treatment among MC38, CT26 and 4T1 tumors, resident T cells were considered as a prerequisite for the effectiveness of combo treatment. These findings demonstrated that Rh2 potentiated the anti-cancer effect of PD-L1 blockade via promoting the T cells infiltration and activation, which shed a new light on the combination strategy to enhance anti-PD-L1 immunotherapy by using natural product Rh2.

Using anti-PD-L1 antibody conjugated gold nanoshelled poly (Lactic-co-glycolic acid) nanocapsules loaded with doxorubicin: A theranostic agent for ultrasound imaging and photothermal/chemo combination therapy of triple negative breast cancer.

Triple negative breast cancer (TNBC) has the worst prognosis of all breast cancers, and it is difficult to progress through traditional chemotherapy. Therefore, the treatment of TNBC urgently requires agents with effective diagnostic and therapeutic capabilities. In this study, we obtained programmed death-ligand 1 (PD-L1) antibody conjugated gold nanoshelled poly(lactic-co-glycolic acid) (PLGA) nanocapsules (NCs) encapsulating doxorubicin (DOX) (DOX@PLGA@Au-PD-L1 NCs). PLGA NCs encapsulating DOX were prepared by a modified single-emulsion oil-in-water (O/W) solvent evaporation method, and gold nanoshells were formed on the surface by gold seed growth method, which were coupled with PD-L1 antibodies by carbodiimide method. The fabricated DOX@PLGA@Au-PD-L1 NCs exhibited promising contrast enhancement in vitro ultrasound imaging. Furthermore, DOX encapsulated in NCs displayed good pH-responsive and photo-triggered drug release properties. After irradiating 200 μg/mL NCs solution with a laser for 10 min, the solution temperature increased by nearly 23°C, indicating that the NCs had good photothermal conversion ability. The targeting experiments confirmed that the NCs had specific target binding ability to TNBC cells overexpressing PD-L1 molecules. Cell experiments exhibited that the agent significantly reduced the survival rate of TNBC cells through photochemotherapy combination therapy. As a multifunctional diagnostic agent, DOX@PLGA@Au-PD-L1 NCs could be used for ultrasound targeted contrast imaging and photochemotherapy combination therapy of TNBC cells, providing a promising idea for early diagnosis and treatment of TNBC.

Intratumoral nanofluidic system enhanced tumor biodistribution of PD-L1 antibody in triple-negative breast cancer.

Immune checkpoint inhibitors (ICI), pembrolizumab and atezolizumab, were recently approved for treatment-refractory triple-negative breast cancer (TNBC), where those with Programmed death-ligand 1 (PD-L1) positive early-stage disease had improved responses. ICIs are administered systemically in the clinic, however, reaching effective therapeutic dosing is challenging due to severe off-tumor toxicities. As such, intratumoral (IT) injection is increasingly investigated as an alternative delivery approach. However, repeated administration, which sometimes is invasive, is required due to rapid drug clearance from the tumor caused by increased interstitial fluid pressure. To minimize off-target drug biodistribution, we developed the nanofluidic drug-eluting seed (NDES) platform for sustained intratumoral release of therapeutic via molecular diffusion. Here we compared drug biodistribution between the NDES, intraperitoneal (IP) and intratumoral (IT) injection using fluorescently labeled PD-L1 monoclonal antibody (αPD-L1). We used two syngeneic TNBC murine models, EMT6 and 4T1, that differ in PD-L1 expression, immunogenicity, and transport phenotype. We investigated on-target (tumor) and off-target distribution using different treatment approaches. As radiotherapy is increasingly used in combination with immunotherapy, we sought to investigate its effect on αPD-L1 tumor accumulation and systemic distribution. The NDES-treated cohort displayed sustained levels of αPD-L1 in the tumor over the study period of 14 days with significantly lower off-target organ distribution, compared to the IP or IT injection. However, we observed differences in the biodistribution of αPD-L1 across tumor models and with radiation pretreatment. Thus, we sought to extensively characterize the tumor properties via histological analysis, diffusion evaluation and nanoparticles contrast-enhanced CT. Overall, we demonstrate that ICI delivery via NDES is an effective method for sustained on-target tumor delivery across tumor models and combination treatments.

A study of programmed death-1/programmed death ligand and iodine-induced autoimmune thyroiditis in NOD.H-2h4 mice.

Excess iodine will trigger the occurrence of autoimmune thyroiditis (AIT), and programmed death-1 (PD-1)/programmed death ligand (PD-L) will also contribute to the development of AIT. The purpose of this study was to explore the role that negative regulatory signals mediated by PD-1/PD-L play in the development of spontaneous autoimmune thyroiditis (SAT) in NOD.H-2h4 mice when they are exposed to iodine. Programmed death ligand 1 (PD-L1) antibody was administered intraperitoneally to NOD.H-2h4 mice. The relevant indicators were determined by flow cytometry, real-time quantitative polymerase chain reaction, enzyme-linked immunosorbent assay, immunohistochemistry, pathological hematoxylin and eosin staining, and arsenic-cerium catalytic spectrophotometry. Results showed that the level of urinary iodine, the level of thyroid lymphocyte infiltration, the level of thyroglobulin antibodies (TgAb) and interferon (IFN-γ)/tumor necrosis factor (TNF-α)/interleukin (IL-2)/IL-17, and the relative expression of PD-1/PD-L1/programmed death-2 (PD-L2) increased with the intervention of excess iodine. After the intervention of the PD-L1 antibody, the expression of PD-1/PD-L1/PD-L2 in different degrees was inhibited, but the level of thyroid lymphocyte infiltration and serum TgAb/IFN-γ/TNF-α/ IL-2/IL-17 did not decrease. Collectively, although PD-1/PD-L participates in the occurrence of SAT and induces inflammation, administration of the PD-L1 antibody does not effectively improve the pathological process of SAT. More research is needed to determine whether PD-1/PD-L intervention can treat autoimmune thyroid disease.

Traditional Chinese medicine inhibits PD-1/PD-L1 axis to sensitize cancer immunotherapy: a literature review.

The Programmed death-1 (PD-1) and its programmed death-ligand 1 (PD-L1) comprise the PD-1/PD-L1 axis and maintain tumor immune evasion. Cancer immunotherapy based on anti-PD-1/PD-L1 antibodies is the most promising anti-tumor treatment available but is currently facing the thorny problem of unsatisfactory outcomes. Traditional Chinese Medicine (TCM), with its rich heritage of Chinese medicine monomers, herbal formulas, and physical therapies like acupuncture, moxibustion, and catgut implantation, is a multi-component and multi-target system of medicine known for enhancing immunity and preventing the spread of disease. TCM is often used as an adjuvant therapy for cancer in clinical practices, and recent studies have demonstrated the synergistic effects of combining TCM with cancer immunotherapy. In this review, we examined the PD-1/PD-L1 axis and its role in tumor immune escape while exploring how TCM therapies can modulate the PD-1/PD-L1 axis to improve the efficacy of cancer immunotherapy. Our findings suggest that TCM therapy can enhance cancer immunotherapy by reducing the expression of PD-1 and PD-L1, regulating T-cell function, improving the tumor immune microenvironment, and regulating intestinal flora. We hope this review may serve as a valuable resource for future studies on the sensitization of immune checkpoint inhibitors (ICIs) therapy.

Abstract 1878: Preclinical development of a novel bispecific mAb-Trap fusion protein, IMM2520, targeting both PD-L1 and CD47 as cancer immunotherapy

Abstract The programmed cell death protein 1 (PD-1) immune checkpoint is well known in its ability to attenuate T cell-mediated immune responses in tumors expressing its ligand, programmed death-ligand 1 (PD-L1). CD47, a cell surface molecule in the immunoglobulin superfamily, is another established target overexpressed on various malignant cells and acts as an innate inhibitory checkpoint by interrupting the phagocytosis of tumor cells and downstream activation of innate responses. It has been reported that the simultaneous blockade on both CD47 and PD-L1 checkpoints inhibited tumor growth and circulating tumor cells metastasis more potently than a single antibody inhibition or blank control in the 4T1 tumor mouse model in vivo. IMM2520 is an antibody-receptor (mAb-Trap) fusion protein consisting of recombinant human SIRPα and anti- PD-L1 antibody, thereby targeting CD47 and PD-L1 to antagonize both innate and adaptive immune checkpoint pathways. IMM2520 binds to PD-L1 on the tumor cell membrane and restores the immune response of T cells. IMM2520 also reverses the inhibitory effect of tumor cells on macrophages by blocking the binding of CD47 on the tumor cell to SIRPα on macrophages. In vitro studies have demonstrated that IMM2520 not only possesses a potent binding activity to CD47 (EC50 = 0.8 nM) and PD-L1 (EC50 = 0.09 nM) respectively, but also exhibits a strong activity in blocking PD-1/PD-L1 binding (IC50 = 0.06 - 1.0 nM). IMM2520 also showed a potent antibody-dependent cellular cytotoxicity (ADCC, EC50 = 1.54 ng/ml) against Raji-PDL1 and induced a strong antibody-dependent cellular phagocytosis (ADCP, EC50 = 0.04 nM) activity (THP-1 against Raji-PDL1). In vivo efficacy study with CT26-hPD-L1/hCD47 colon cancer model demonstrated that IMM2520 at 3 mg/kg significantly reduced tumor volume (TGITV = 90.12%, P&amp;lt;0.01 vs Vehicle). Interestingly, IMM2520 demonstrated a potent and significantly higher anti-tumor activities than IMM01 (a SIRPα-Fc fusion protein) and IMM2505 (also a CD47XPD-L1 mAb-Trap, but the variable region sequence of this PD-L1 antibody is identical to atezolizumab). IMM2520 at dose of 6 mg/kg completely eradicated the established tumors. In another in vivo efficacy study with MC38-hCD47/hPD-L1 colon cancer model, IMM2520 demonstrated a significant anti-tumor activity in a dose-dependent manner at doses between 2 mg/kg to 20 mg/kg. Given its potent preclinical anti-tumor activity as well as the favorable safety profile, IMM2520 may serve as a potent immunotherapy for multiple cancer types by targeting PD-L1 and CD47 on tumor cells. Citation Format: Wenzhi Tian, Song Li, Dianze Chen, Wenqi Zhu, Yanan Yang, Dandan Liu, Huiqin Guo, Chunmei Yang, Li Zhang, Wei Zhang, Xiaoping Tu, Liang Peng, Gui Zhao, Ruliang Zhang, Fan Zhang, Frank Gan. Preclinical development of a novel bispecific mAb-Trap fusion protein, IMM2520, targeting both PD-L1 and CD47 as cancer immunotherapy [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 1878.