OBJECTIVES: To study the molecular mechanisms of LDH-loaded si-NEAT1 for regulating paclitaxel resistance and tumor-associated macrophage (TAM) polarization in breast cancer. METHODS: qRT-PCR and Western blotting were used to detect the expression of lncRNA NEAT1, miR-133b, and PD-L1 in breast cancer SKBR3 cells and paclitaxel-resistant SKBR3 cells (SKBR3-PR). The effects of transfection with si-NEAT1 and miR-133b mimics on MRP, MCRP and PD-L1 expressions and cell proliferation, migration and apoptosis were investigated using qRT-PCR, Western blotting, scratch and Transwell assays, and flow cytometry. Rescue experiments were conducted using si-NEAT1 and miR-133b inhibitor. Human THP-1 macrophages were cultured in the presence of conditioned media (CM) derived from SKBR3 and SKBR3-PR cells with or with si-NEAT1 transfection for comparison of IL-4-induced macrophage polarization by detecting the surface markers. LDH@si-NEAT1 nanocarriers were constructed, and their effects on MRP, MCRP and PD-L1 expressions and cell behaviors of the tumor cells were examined. THP-1 cells were treated with the CM from LDH@si-NEAT1-treated tumor cells, and the changes in their polarization were assessed. RESULTS: SKBR3-PR cells showered significantly upregulated NEAT1 and PD-L1 expressions and lowered miR-133b expression as compared with their parental cells. Transfection with si-NEAT1 and miR-133b mimics inhibited viability, promoted apoptosis and enhanced MRP and BCRP expressions in SKBR3-PR cells. NEAT1 knockdown obvious upregulated miR-133b and downregulated PD-L1, MRP and BCRP expressions. The CM from SKBR3-PR cells obviously promoted M2 polarization of THP-1 macrophages, which was significantly inhibited by CM from si-NEAT1-transfected cells. Treatment with LDH@si-NEAT1 effectively inhibited migration and invasion, promoted apoptosis, and reduced MRP, BCRP and PD-L1 expressions in the tumor cells. The CM from LDH@si-NEAT1-treated SKBR3-PR cells significantly downregulated Arg-1, CD163, IL-10, and PD-L1 and upregulated miR-133b expression in THP-1 macrophages. CONCLUSIONS LDH@si-NEAT1 reduces paclitaxel resistance of breast cancer cells and inhibits TAM polarization by targeting the miR-133b/PD-L1 axis.
Humans ; MicroRNAs/genetics* ; RNA, Long Noncoding/genetics* ; Paclitaxel/pharmacology* ; Breast Neoplasms/metabolism* ; Drug Resistance, Neoplasm ; B7-H1 Antigen/metabolism* ; Cell Line, Tumor ; Female ; Tumor-Associated Macrophages ; Apoptosis ; Cell Proliferation ; Macrophages ; Cell Movement

Epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) are currently the first-line standard of care for patients with non-small cell lung cancer (NSCLC) that harbor EGFR mutations. Nevertheless, resistance to EGFR-TKIs is inevitable. In recent years, although immune checkpoint inhibitors (ICIs) have significantly shifted the treatment paradigm in advanced NSCLC without driver mutation, clinical benefits of these agents are limited in patients with EGFR-mutated NSCLC. Compared with wild-type tumors, tumors with EGFR mutations show more heterogeneity in the expression level of programmed cell death ligand 1 (PD-L1), tumor mutational burden (TMB), and other tumor microenvironment (TME) characteristics. Whether ICIs are suitable for NSCLC patients with EGFR mutations is still worth exploring. In this review, we summarized the clinical data with regard to the efficacy of ICIs in patients with EGFR-mutated NSCLC and deciphered the unique TME in EGFR-mutated NSCLC.
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Humans ; Carcinoma, Non-Small-Cell Lung/genetics* ; Lung Neoplasms/genetics* ; ErbB Receptors/metabolism* ; Immunotherapy ; Mutation ; B7-H1 Antigen/genetics* ; Protein Kinase Inhibitors/pharmacology* ; Tumor Microenvironment

Immunotherapies based on immune checkpoint blockade (ICB) have significantly improved patient outcomes and offered new approaches to cancer therapy over the past decade. To date, immune checkpoint inhibitors (ICIs) of CTLA-4 and PD-1/PD-L1 represent the main class of immunotherapy. Blockade of CTLA-4 and PD-1/PD-L1 has shown remarkable efficacy in several specific types of cancers, however, a large subset of refractory patients presents poor responsiveness to ICB therapy; and the underlying mechanism remains elusive. Recently, numerous studies have revealed that metabolic reprogramming of tumor cells restrains immune responses by remodeling the tumor microenvironment (TME) with various products of metabolism, and combination therapies involving metabolic inhibitors and ICIs provide new approaches to cancer therapy. Nevertheless, a systematic summary is lacking regarding the manner by which different targetable metabolic pathways regulate immune checkpoints to overcome ICI resistance. Here, we demonstrate the generalized mechanism of targeting cancer metabolism at three crucial immune checkpoints (CTLA-4, PD-1, and PD-L1) to influence ICB therapy and propose potential combined immunotherapeutic strategies co-targeting tumor metabolic pathways and immune checkpoints.
Humans ; Antibodies, Monoclonal/pharmacology* ; B7-H1 Antigen/antagonists & inhibitors* ; CTLA-4 Antigen/antagonists & inhibitors* ; Immune Checkpoint Inhibitors/pharmacology* ; Neoplasms/drug therapy* ; Programmed Cell Death 1 Receptor ; Tumor Microenvironment

The immune checkpoint programmed cell death-ligand 1(PD-L1)-mediated immunosuppression is among the important features of tumor. PD-L1, an immunosuppressant, can induce T cell failure by binding to programmed cell death-1(PD-1). Thus, the key to restoring the function of T cells is inhibiting the expression of PD-L1. The Chinese medicinal Atractylodis Macrocephalae Rhizoma(AMR) has the anti-tumor, anti-inflammatory, antioxidant, and hypoglycemic activities, and the polysaccharide in AMR(PAMR) plays a crucial role in immunoregulation, but the influence on the immune checkpoints which are closely related to immunosuppression has not been reported. MicroRNA-34 a(miR-34 a) expression in esophageal carcinoma tissue is significantly lower than that in normal tissue. This study aims to investigate the inhibitory effect of PAMR on esophageal carcinoma cells, and the relationship between its inhibitory effect on PD-L1 expression and miR-34 a, which is expected to clarify the anti-tumor mechanism of PAMR. Firstly, different human esophageal carcinoma cell lines(EC9706, EC-1, TE-1, EC109 cells) were screend out, and expression of PD-L1 was determined. Then, EC109 cells, with high expression of PD-L1, were selected for further experiment. The result showed that PAMR suppressed EC109 cell growth. According to the real-time quantitative PCR(qPCR) and Western blot, it significantly suppressed the mRNA and protein expression of PD-L1, while promoting the expression of tumor suppressor miR-34 a. The confocal microscopy and luci-ferase assay proved that PAMR alleviated the inhibitory effect of PD-L1 while blocked miR-34 a. Additionally, the expression of PD-L1 was controlled by miR-34 a, and the combination of miR-34 a inhibitor with high-dose PAMR reversed the inhibitory effect of PAMR on PD-L1 protein expression. Thus, the PAMR may inhibit PD-L1 by increasing the expression of miR-34 a and regulating its downstream target genes. In conclusion, PAMR inhibits the expression of PD-L1 mainly by inducing miR-34 a.
B7-H1 Antigen/pharmacology* ; Carcinoma ; Cell Proliferation ; Humans ; MicroRNAs/metabolism* ; Polysaccharides/pharmacology*

Objective: To investigate the effect of CD33-targeted bi-specific and tri-specific T-cell engagers on T-cell proliferation and explore their cytotoxicity on leukemia cells. Methods: The CD33-targeted bi-specific T-cell engager (CD33-BiTE) and tri-specific T-cell engager (CD33-TriTE) expression vectors were successfully constructed and expressed through a eukaryotic cell expression system. CD33-BiTE and CD33-TriTE were purified by affinity chromatography. The effects of CD33-BiTE and CD33-TriTE on T cells were analyzed through in vitro experiments. Results: ① CD33-BiTE and CD33-TriTE were successfully constructed and purified and could compete with flow cytometry antibodies for binding to the target cells. ② After 12 days of co-culture with CD33-BiTE and CD33-TriTE, the number of human T cells were expanded to 33.89±19.46 and 81.56±23.62 folds, respectively. CD33-TriTE induced a stronger proliferation of T cells than CD33-BiTE (P<0.05) . ③ Both CD33-BiTE and CD33-TriTE induced specific dose-dependent cytotoxicity on CD33(+) leukemia cells. ④ Compared to CD33-TriTE, leukemia cells were prone to express PD-L1 when co-cultured with T cells and CD33-BiTE. CD33-TriTE induced powerful cytotoxicity on leukemia cells with high PD-L1 expression. Conclusion: CD33-BiTE and CD33-TriTE expression vectors were constructed, and fusion proteins were expressed in eukaryotic cells. Our results support the proliferative and activating effects of BiTE and TriTE on T cells. Compared to that of CD33-BiTE, CD33-TriTE induced a stronger proliferative effect on T cells and a more powerful cytotoxicity on leukemia cells with high PD-L1 expression.
B7-H1 Antigen/pharmacology* ; Humans ; Leukemia, Myeloid, Acute/metabolism* ; Sialic Acid Binding Ig-like Lectin 3/pharmacology* ; T-Lymphocytes

Interferon-γ (IFN-γ), a key effector molecule in anti-tumor immune response, has been well documented to correlate with the intratumoral infiltration of immune cells. Of interest, however, a high level of IFN-γ has been reported in salivary adenoid cystic carcinoma (SACC), which is actually a type of immunologically cold cancer with few infiltrated immune cells. Investigating the functional significance of IFN-γ in SACC would help to explain such a paradoxical phenomenon. In the present study, we revealed that, compared to oral squamous cell carcinoma cells (a type of immunologically hot cancer), SACC cells were less sensitive to the growth-inhibition effect of IFN-γ. Moreover, the migration and invasion abilities of SACC cells were obviously enhanced upon IFN-γ treatment. In addition, our results revealed that exposure to IFN-γ significantly up-regulated the level of programmed death ligand 1 (PD-L1) on SACC cell-derived small extracellular vesicles (sEVs), which subsequently induced the apoptosis of CD8⁺ T cells through antagonizing PD-1. Importantly, it was also found that SACC patients with higher levels of plasma IFN-γ also had higher levels of circulating sEVs that carried PD-L1 on their surface. Our study unveils a mechanism that IFN-γ induces immunosuppression in SACC via sEV PD-L1, which would account for the scarce immune cell infiltration and insensitivity to immunotherapy.
B7-H1 Antigen/metabolism* ; CD8-Positive T-Lymphocytes/pathology* ; Carcinoma, Adenoid Cystic/pathology* ; Carcinoma, Squamous Cell/pathology* ; Cell Line, Tumor ; Humans ; Immunosuppression Therapy ; Interferon-gamma/pharmacology* ; Mouth Neoplasms/metabolism* ; Programmed Cell Death 1 Receptor/metabolism* ; Salivary Gland Neoplasms/pathology*

Programmed cell death-1 (PD-1)/programmed cell death-ligand 1 (PD-L1) checkpoint blockades have dramatically changed the treatment of non-small cell lung cancer (NSCLC). But we still have no definite biomarkers that may predict the efficacy of treatment by PD-1/PD-L1 inhibitors. In the 18th World Conference on Lung Cancer, the biomarkers that may predict the efficacy of treatment by PD-1/PD-L1 inhibitors in patients with lung cancer has been a popular topic, and it has huge potential in the future. In order to enable more patients to get more benefits from treatment, researchers are looking forward to finding the optimum biomarkers. By organizing and summarizing the information about the biomarkers predicting PD-1/PD-L1 in patients with lung cancer, this review mainly focused on the following six aspects to introduce: expression of PD-L1; tumor mutational burden and the ability of mutation repair, malignant tumor driver mutation, biomarker of immunological effect, blood cell account, comprehensive analysis model. We are hoping to help doctors to find the best biomarker, then much more lung cancer patients could obtain antitumor effects in PD-1/PD-L1 inhibitors treatment.
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Antineoplastic Agents ; pharmacology ; therapeutic use ; B7-H1 Antigen ; antagonists & inhibitors ; Biomarkers, Tumor ; metabolism ; Carcinoma, Non-Small-Cell Lung ; drug therapy ; genetics ; metabolism ; Humans ; Lung Neoplasms ; drug therapy ; genetics ; metabolism ; Programmed Cell Death 1 Receptor ; antagonists & inhibitors

The thioredoxin system plays a role in a variety of physiological functions, including cell growth, differentiation, apoptosis, tumorigenesis, and immunity. We previously confirmed that butaselen (BS), a novel thioredoxin reductase inhibitor, can inhibit the growth of various human cancer cell lines, yet the underlying mechanism remains elusive. In this study, we investigated the anti-tumor effect of BS in vivo through regulating the immune system of KM mice. We found that BS inhibits tumor proliferation by promoting the activation of splenic lymphocytes in mice. BS can elevate the percentage of CD₄^-CD₈⁺ T lymphocytes and the secretion of downstream cytokines in mice via down-regulating the expression of programmed death-ligand 1 (PD-L1) on the tumor cells' surface in vivo. Further study in HepG2 and BEL-7402 cells showed that decrease of PD-L1 level after BS treatment was achieved by inhibiting signal transducer and activator of transcription 3 (STAT3) phosphorylation. Taken together, our results suggest that BS has a role in promoting the immune response by reducing PD-L1 expression via the STAT3 pathway, and subsequently suppresses tumorigenesis.
Animals ; Antineoplastic Agents/pharmacology* ; B7-H1 Antigen/antagonists & inhibitors* ; Benzene Derivatives/therapeutic use* ; CD8-Positive T-Lymphocytes/drug effects* ; Hep G2 Cells ; Humans ; Liver Neoplasms/pathology* ; Male ; Mice ; Organoselenium Compounds/therapeutic use* ; STAT3 Transcription Factor/physiology* ; Thioredoxin-Disulfide Reductase/antagonists & inhibitors* ; Tumor Burden/drug effects*

OBJECTIVETo establish the mouse model for the expression of PD-L1 by hydrodynamic injection and to study the effects of myeloablative conditioning on hydrodynamic injection-mediated PD-L1 expression.

METHODSPlasmid amplification, hydrodynamic injection, collagenase perfusion, real time PCR, ELISA and flow cytometry were applied to test the expression and function of PD-L1. Also, animal models were set up to test the effects of chemical or radiactive myeloablative conditioning on hydrodynamic injection-mediated PD-L1 expression.

RESULTSThe expression of PD-L1 mRNA and protein could be detected as early as 8 h after hyrodynamic injection and reached peak expression by 24 h, and returned to baseline level by 7 d after injection. Serum PD-L1 level reached to 100 µg/ml as early as 24 h after injection and plateaued at 7 d after injection. Serum PD-L1 persisted for 3 weeks and declined to baseline after 1 month of hydrodynamic injection. The PD-L1 function induced by hydrodynamic injection was consistent with literature reports. At each time point, the PD-L1 expression was not different significantly between the myeloablative conditioning group and control group; the mice transfected with PD-L1 showed a higher survival rate than that in control group.

CONCLUSIONMyeloablative conditioning does not affect hydrodynamic injection-mediated PD-L1 expression, indicating that the PD-L1 can be used in HSCT mouse model.

Animals ; B7-H1 Antigen ; pharmacology ; Disease Models, Animal ; Flow Cytometry ; Hydrodynamics ; Injections ; Mice ; Myeloablative Agonists ; pharmacology ; RNA, Messenger ; Transfection ; Transplantation Conditioning

In order to investigate the effect of PD-L1 on lymphoma cell proliferation and chemotherapy resistance, and explore a new and promising approach for therapy of lymphomas. The level of PD-L1 expression in tissues of patients with lymphoma and cell lines were detected by immunohistochemistry and flow cytometry. Both the stable high-PDL1-A20 cell strain and low-PDL1-A20 cell strain were sorted by flow cytometry, then inoculated into BALB/c mice as to establish a lymphoma bearing mouse model for observing tumor genesis. Finally, the effect of PD-L1 on routinely chemotherapy drug-cisplatin were observed. The results showed that the PD-L1 highly and widely expressed in lymphoma tissue and cell strains, the stable high-PD-L1 cell strain sorted by flow cytometry have higher lymphoma genesis than that of low-PD-L1 cell strain. It is concluded that PD-L1 can promote lymphoma genesis, meanwhile the PD-L1 may resist effect of cisplatin on lymphoma cells through anti-apoptosis.
Animals ; Apoptosis ; B7-H1 Antigen ; metabolism ; Cell Line, Tumor ; Cell Proliferation ; Cisplatin ; pharmacology ; Drug Resistance, Neoplasm ; Lymphoma ; drug therapy ; metabolism ; pathology ; Mice ; Mice, Inbred BALB C ; Mice, Inbred C57BL