PD-L1 Signaling Pathway Research Articles

RETRACTED: MiR-374b increases the CIK expression and mediates biological function changes in cervical cancer cells by targeting the PD-1/PD-L1 signaling pathway

To investigate the role of miR-374b in medicating biological function changes in cervical cancer cells by increasing the cytokine-induced killer (CIK) expression. Venous blood of 62 cervical cancer patients and 58 healthy individuals including Human cervical cancer cell line (HeLa) and normal human uterine smooth muscle cells (HUSMC) were tested for expression of miR-374b, PD-1, and PD-L1. sh-PD-1, si-PD-1, NC, miR-374b-inhibitor, and miR-374b-mimics were transfected into HeLa cells, and expression of miR-374b, PD-1, and PD-L1 was determined by a qRT-PCR assay, and the proliferation and apoptosis of the cells were detected using a MTT assay and flow cytometry, respectively. PD-1 was highly expressed in cervical cancer, while miR-374b is lowly expressed in it, and the area-under-the-curve (AUC) of both PD-1 and miR-374b was larger than 0.8. The dual luciferase reporter assay confirmed relationship between PD-1 and miR-374b. Expression of PD-1 in HeLa cells was significantly down-regulated after transfection of miR-374b-mimics. Compared with the CIK + NC group, the CIK + miR-374b-mimics group and the CIK + siRNA-PD-1 group showed a significant decrease in the relative mRNA expression of PD-1, compared with other group showed significantly lowered activity of HeLa cells, and the two groups showed significantly reduced tumor volume. MiR-374b increases the CIK expression and mediates biological function changes in cervical cancer cells by targeting the PD-1/PD-L1 signaling pathway, so it is expected to be a potential therapeutic target for cervical cancer.

Role of PD-L1 in Gut Mucosa Tolerance and Chronic Inflammation.

The gastrointestinal (GI) mucosa is among the most complex systems in the body. It has a diverse commensal microbiome challenged continuously by food and microbial components while delivering essential nutrients and defending against pathogens. For these reasons, regulatory cells and receptors are likely to play a central role in maintaining the gut mucosal homeostasis. Recent lessons from cancer immunotherapy point out the critical role of the B7 negative co-stimulator PD-L1 in mucosal homeostasis. In this review, we summarize the current knowledge supporting the critical role of PD-L1 in gastrointestinal mucosal tolerance and how abnormalities in its expression and signaling contribute to gut inflammation and cancers. Abnormal expression of PD-L1 and/or the PD-1/PD-L1 signaling pathways have been observed in the pathology of the GI tract. We also discuss the current gap in our knowledge with regards to PD-L1 signaling in the GI tract under homeostasis and pathology. Finally, we summarize the current understanding of how this pathway is currently targeted to develop novel therapeutic approaches.

Key Immune Checkpoint PD-1/PD-L1 Signaling Pathway Components in the Blood Serum from Patients with Bone Tumors

The levels of sPD-1 and sPD-L1 were analyzed in blood serum of 132 patients (age 14-70 years) with primary bone tumors: osteosarcoma (N=39), chondrosarcoma (N=42), Ewing sarcoma (N=9), chordoma (N=12), giant-cell bone tumor (GCBT) (N=16), benign neoplasms (N=14) and in and practically healthy subjects (age 19-58 years; N=27). sPD-L1 levels in all studied bone neoplasms were significantly higher than in the control. Serum sPD-1 level in GCBT patients was significantly higher than in the control, benign neoplasms, chondrosarcoma, and chordoma patients, but did not differ from osteosarcoma group. sPD-1 concentration in Ewing sarcoma was significantly higher than in chordoma and chondrosarcoma, but did not differ from the control. sPD-1 level in chondrosarcoma patients was also lower than in osteosarcoma, Ewing sarcoma, and in the control. Both sPD-1 and sPD-L1 concentrations were not significantly associated with the type of affected bone, process localization, disease stage, tumor histological grade, patients' age and sex. These results suggest the possibility of using these biological markers for preliminary assessment of the character of the process in the bone.

Synergistic anti-liver cancer effects of curcumin and total ginsenosides.

BACKGROUNDLiver cancer is the sixth most frequently occurring cancer in the world and the fourth most common cause of cancer mortality. The pathogenesis of liver cancer is closely associated with inflammation and immune response in the tumor microenvironment. New therapeutic agents for liver cancer, which can control inflammation and restore cellular immunity, are required. Curcumin (Cur) is a natural anti-inflammatory drug, and total ginsenosides (TG) are a commonly used immunoregulatory drug. Of note, both Cur and TG have been shown to exert anti-liver cancer effects.AIMTo determine the synergistic immunomodulatory and anti-inflammatory effects of Cur combined with TG in a mouse model of subcutaneous liver cancer.METHODSA subcutaneous liver cancer model was established in BALB/c mice by a subcutaneous injection of hepatoma cell line. Animals were treated with Cur (200 mg/kg per day), TG (104 mg/kg per day or 520 mg/kg per day), the combination of Cur (200 mg/kg per day) and TG (104 mg/kg per day or 520 mg/kg per day), or 5-fluorouracil combined with cisplatin as a positive control for 21 d. Tumor volume was measured and the protein expression of programmed cell death 1 and programmed cell death 1 ligand 1 (PD-L1), inflammatory indicators Toll like receptor 4 (TLR4) and nuclear factor-κB (NF-κB), and vascular growth-related factors nitric oxide synthases (iNOS) and matrix metalloproteinase 9 were analyzed by Western blot analysis. CD4+CD25+Foxp3+ regulatory T cells (Tregs) were counted by flow cytometry.RESULTSThe combination therapy of Cur and TG significantly inhibited the growth of liver cancer, as compared to vehicle-treated animals, and TG showed dose dependence. Cur combined with TG-520 markedly decreased the protein expression of PD-L1 (P < 0.0001), while CD4+CD25+Foxp3+ Tregs regulated by the PD-L1 signaling pathway exhibited a positive correlation with PD-L1. Cur combined with TG-520 also inhibited the cascade action mediated by NF-κB (P < 0.0001), thus inhibiting the TLR4/NF-κB signalling pathway (P = 0.0088, P < 0.0001), which is associated with inflammation and acts on PD-L1. It also inhibited the NF-κB-MMP9 signalling pathway (P < 0.0001), which is associated with tumor angiogenesis.CONCLUSIONCur combined with TG regulates immune escape through the PD-L1 pathway and inhibits liver cancer growth through NF-κB-mediated inflammation and angiogenesis.

Mechanism on moxibustion for rheumatoid arthritis based on PD-1/PD-L1 signaling pathway

To explore the mechanism of moxibustion on the treatment of rheumatoid arthritis (RA) in the perspective of programmed cell death-1 and its ligand 1 (PD-1/PD-L1). A total of 30 Japanese big ear white rabbits were randomly divided into a control group, a model group and a moxibustion group, 10 rabbits in each one. In the model group and the moxibustion group, RA model was prepared by the injection of Freund's complete adjuvant (FCA) into the hind knee joint cavities of each rabbit. In the control group, 0.9% sodium chloride solution of the same dose was injected. On the 8th day of experiment, in the moxibustion group, moxibustion was applied to "Shenshu" (BL 23) and "Zusanli" (ST 36), 5 cones at each acupoint, on the bilateral sides alternatively, once a day, 6 treatments as one course, with an interval of 1 days between the treatment courses. Totally, 3 courses of treatment were required. On the 1st, 7th, 14th, 21st and 28th days of experiment, successively, the circumference of the bilateral knee joints was measured with the tape. On the 28th day of experiment, H.E. staining was adopted to observe the histopathological morphology and to evaluate the score of knee synovial tissue. ELISA was used to determined the concentrations of soluble PD-1 (sPD-1) and its ligand 1 (sPD-L1), the interleukin 2 (IL-2) and IL-17 in knee synovial fluid and the concentrations of sPD-1 and sPD-L1 in serum. The histochemistry method was used to determine the expressions of membrane PD-1 (mPD-1) and its ligand 1 (mPD-L1) in spleen tissue. On the 14th, 21st and 28th days of experiment, the circumference of both knee joints was increased in each of the rabbits in the model group as compared with the control group (P<0.01), and it was reduced significantly in the moxibustion group as compared with the model group (P<0.01). Compared with the control group, the hyperplasia of synovial tissue and fibrous tissue, as well as inflammatory cell infiltration were increased obviously in the model group (P<0.01), and they were reduced significantly in the moxibustion group as compared with the model group (P<0.01, P<0.05). Compared with the control group, the concentrations of IL-2 and IL-17 in knee synovial fluid were increased in the rabbits of the model group (P<0.01). Compared with the model group, after the intervention with moxibustion, the concentrations of IL-2 and IL-17 in knee synovial fluid were reduced in the rabbits of the moxibustion group (P<0.05). Compared with the control group, the concentrations of sPD-1 and sPD-L1 in knee synovial fluid and serum in the rabbits of the model group were all increased (P<0.05). Compared with the model group, the concentration of sPD-1 in the knee synovial fluid and serum were reduced in the rabbits of moxibustion group (P<0.05). Compared with the control group, the expressions of mPD-1 and mPD-L1 in spleen tissue were increased obviously in the rabbits of the model group (P<0.05). Compared with the model group, the expression of mPD-L1 in spleen tissue was up-regulated in the rabbits of the moxibustion group (P<0.05). Moxibustion could inhibit the over-activation of T cells by enhancing the negative regulation of PD-1/PD-L1 signaling pathway so as to play its effect in treatment of RA.

Heat Shock Proteins and PD-1/PD-L1 as Potential Therapeutic Targets in Myeloproliferative Neoplasms.

Simple SummaryMyeloproliferative neoplasms (MPN), which are a heterogeneous group of rare disorders that affect blood cell production in bone marrow, present many significant challenges for clinicians. Though considerable progress has been made, in particular with the JAK1/2 inhibitor ruxolitinib, more effective alternative therapeutic approaches are needed. In the search for new and more efficient therapies, heat shock proteins, also known as stress proteins, and the programmed cell death 1 (PD-1)/programmed death ligand 1 (PD-L1) immune checkpoint axis have been found to be of great interest in hematologic malignancies. Here, we review the therapeutic potential of stress protein inhibitors in the management of patients diagnosed with MPN and summarize the accumulating evidence of the role of the PD-1/PD-L1 axis in MPN in order to provide perspectives on future therapeutic opportunities relative to the inhibition of these targets.Myeloproliferative neoplasms (MPN) are a group of clonal disorders that affect hematopoietic stem/progenitor cells. These disorders are often caused by oncogenic driver mutations associated with persistent Janus kinase (JAK)/signal transducer and activator of transcription (STAT) signaling. While JAK inhibitors, such as ruxolitinib, reduce MPN-related symptoms in myelofibrosis, they do not influence the underlying cause of the disease and are not curative. Due to these limitations, there is a need for alternative therapeutic strategies and targets. Heat shock proteins (HSPs) are cytoprotective stress-response chaperones involved in protein homeostasis and in many critical pathways, including inflammation. Over the last decade, several research teams have unraveled the mechanistic connection between STAT signaling and several HSPs, showing that HSPs are potential therapeutic targets for MPN. These HSPs include HSP70, HSP90 (chaperoning JAK2) and both HSP110 and HSP27, which are key factors modulating STAT3 phosphorylation status. Like the HSPs, the PD-1/PD-L1 signaling pathway has been widely studied in cancer, but the importance of PD-L1-mediated immune escape in MPN was only recently reported. In this review, we summarize the role of HSPs and PD-1/PD-L1 signaling, the modalities of their experimental blockade, and the effect in MPN. Finally, we discuss the potential of these emerging targeted approaches in MPN therapy.

Synthesis and Evaluation of Biphenyl-1,2,3-Triazol-Benzonitrile Derivatives as PD-1/PD-L1 Inhibitors.

In this study, we designed and synthesized a series of 3-(4-((5-((2-methylbiphenyl-3-yl) methoxy)-2-(piperazin-1-ylmethyl)phenoxy)methyl)-1H-1,2,3-triazol-1-yl)benzonitrile derivatives and examined the effect of the compounds on the interaction between PD-1 and PD-L1. Among the newly synthesized compounds, compound 7 exhibited the most potent inhibitory activity for PD-1/PD-L1 binding, with an IC50 value being 8.52 μM, through homogeneous time-resolved fluorescence (HTRF) assay. Docking studies indicated that compound 7 can very well interact with PD-L1 dimerization like BMS-202 as a positive control, consistent with the results of the HTRF assay. Compound 7 is thus a promising candidate for further optimization as an inhibitor of the PD-1/PD-L1 signaling pathway.

Effects of PD-1/PD-L1 signaling pathway on intestinal flora in patients with colorectal cancer.

To explore the effects of the programmed death-1/programmed death-ligand 1 (PD-1/PD-L1) signaling pathway on the intestinal flora in patients with colorectal cancer (CRC). A total of 30 CRC patients treated with PD-1 monoclonal antibody therapy in the Oncology Department of our hospital from January 2018 to January 2019, and another 30 patients treated with routine non-immune therapy were enrolled. The feces specimens were collected for sequencing, the CRC model was established, and the 16S rRNA gene sequences in intestinal flora in feces specimens of mice were analyzed. The 3-month progression-free survival could not be predicted through the gene count or abundance of metagenomic species (MGS) in intestinal microflora of patients. The gene count or MGS abundance was related to the clinical progression-free response. There were abundant unclassified Escherichia coli, s_lactobacillus and s_unclassified parasutterella in patients treated with PD-1. The reflection curve of microbiota had an obvious difference in richness(Chao1), but had no apparent difference in diversity (Shannon). The PD-1/PD-L1 signaling pathway can regulate the metabolic activity of intestinal flora, thereby promoting immune surveillance of tumors.

Molecular-guided therapy for disseminated cervical cancer: present and future

Сervical cancer is recognized as one of the leaders in mortality from gynecological oncological diseases. The incidence and mortality from cervical cancer over the past 10 years remained at a consistently high level. For a long time, the only treatment option for metastatic and/or recurrent cervical cancer was cytotoxic chemotherapy, but its results remained extremely unsatisfactory: the 5-year overall survival rate was about 12%. This article is devoted to a review of the current possibilities of targeted and immunotherapy of metastatic and/or recurrent cervical cancer. We reviewed the most recent studies in the field of the effectiveness of antiangiogenic therapy including a critical and detailed analysis of the results of the GOG-240 phase III study. The data of modern literature in the field of immunotherapy using PD-1 / PD-L1 signaling pathway inhibitors in metastatic cervical cancer has been studied. It was found that a significant number of patients (34-95%) showed increased expression of PD-L1 in the tumor tissue, and 3-6% of patients showed a high level of microsatellite instability (MSI) in the tumor, which reveals the possibility of immunotherapy for this disease. We also conducted a review of ongoing clinical studies on the use of targeted and immunotherapy of advanced cervical cancer and the prospects for changing the “landscape” of treatment for this disease were assessed. On the example of a clinical case of treatment of a real patient, the possibilities of modern targeted and immunotherapy of metastatic cancer of the cervix uteri were analyzed, which gave a possibility to ensure long-term survival for the patient with an initially poor prognosis.

A novel immune checkpoint-related seven-gene signature for predicting prognosis and immunotherapy response in melanoma

BackgroundNew emergence of immunotherapy has significantly improved clinical outcome of melanoma patients with advanced and metastatic diseases. We aimed to develop a gene signature based on the expression of PD-1/PD-L1 signaling pathway genes to predict prognosis and immunotherapy response in melanoma patients. MethodsMelanoma samples from The Cancer Genome Atlas (TCGA) database and Gene Expression Omnibus (GEO) were used as the training set and external validation sets respectively. Prognostic genes for overall survival (OS) were identified by univariate Cox regression analysis. Then a multi-gene risk signature was established with the Least Absolute Shrinkage and Selector Operation (LASSO) regression and multivariate Cox regression. The predictive and prognostic value of gene signature was evaluated by Kaplan Meier curve, Time-dependent receiver operating characteristic (ROC) curve, and area under curve (AUC). Gene set enrichment analysis (GSEA) was performed to investigate the discrepantly enriched biological processes between low-risk and high-risk group of melanoma patients. ResultsA seven-gene risk signature (BATF2, CTLA4, EGFR, HLA-DQB1, IKBKG, PIK3R2, PPP3CA) was constructed. The signature was an independent risk factor for OS (hazard ratio = 1.544, p < 0.001) and it could robustly predict OS in both training and validation sets. Besides, high risk scores indicated advanced clinical stage and no response to immunotherapy for melanoma patients. GSEA demonstrated that high risk score was intimately associated with immune response and immune regulation. In conclusion, the novel seven-gene signature could serve as a robust biomarker for prognosis and a potential indicator of immunotherapy response in melanoma.

High-Risk HPV Oncoproteins and PD-1/PD-L1 Interplay in Human Cervical Cancer: Recent Evidence and Future Directions.

Cervical cancer is the fourth most common malignancy in women worldwide and a leading cause of cancer-related mortality in developing countries. Important etiological factors in this cancer are high-risk human papillomaviruses (HPV), as roughly 96% of cervical cancer cases are positive for these oncoviruses. On the other hand, it has been recently pointed out that E6/E7 oncoproteins of high-risk HPV can upregulate the programmed cell death-1/programmed cell death-ligand 1 (PD-1/PD-L1) axis. Likewise, several recent reports showed that checkpoint blockades targeting PD-1/PD-L1 pathways have achieved efficient clinical responses via suppressing cancer progression and improving survival in several types of human cancers including metastatic cervical cancer. In this review, we summarize recent advances in our understanding of the PD-1/PD-L1 signaling pathway and its interaction with high-risk HPV and their oncoproteins, which could have an important impact on the management of HPV-associated cancers including cervical.

NIVACOR: Phase II study of nivolumab in combination with FOLFOXIRI/bevacizumab in first-line chemotherapy for advanced colorectal cancer RASm/BRAFm patients.

TPS4118 Background: FOLFOXIRI (fluorouracil, leucovorin, oxaliplatin, and irinotecan) plus bevacizumab has been shown to be one of the therapeutic regimens in first line with the highest activity profile in patients (pts) with metastatic colorectal cancer (mCRC) unselected for biomolecular alterations. Tumors co-opt the PD-1/PD-L1 signaling pathway as one key mechanism to evade immune destruction. Anti-PD-1 monoclonal antibodies are FDA approved only for DNA mismatch repair deficient/microsatellite instability-high (MMRd/MSI-H), which are only about 5% among all mCRC. Nowadays, there are no data demonstrating anti-PD1 activity in stable and proficient (MMRp/MSS) disease. Another critical therapeutic target is the Vascular Endothelial Growth Factor A (VEGF-A), which acts on endothelial cells to stimulate angiogenesis; his inhibition with bevacizumab increase immune cell infiltration, giving a strong rationale for combining VEGF targeted agents with immune checkpoint inhibitors. Based on evidence, we explore the combination of triplet chemotherapy (FOLFOXIRI) with bevacizumab and nivolumab in pts with mCRC all- RAS/BRAF mutant regardless of microsatellite status. Methods: This is a prospective, open-label, multicentric phase II trial where pts with mCRC RAS/BRAF mutant in first line will receive nivolumab in combination with FOLFOXIRI/Bevacizumab every 2 weeks for 8 cycles followed by maintenance with bevacizumab plus nivolumab every 2 weeks. Bevacizumab will be administered intravenously at dose of 5 mg/kg every 2 weeks and nivolumab intravenously as a flat dose of 240 mg every 2 weeks. The primary endpoint is the overall response rate (ORR) and our hypothesis is that the treatment is able to improve the ORR from 66% to 80%. Secondary endpoints include overall survival, safety, time to progression, duration of response. Collateral translational studies evaluate the tumor mutational burden, and genetic alterations by circulating free DNA (cfDNA) obtained from plasma samples. The trial is open to enrollment, 4 of planned 70 pts have been enrolled. Clinical trial information: EudraCT Number: 2018-002893-38. Clinical trial information: NCT04072198 .

Programmed cell death protein 1 and its ligands regulate immune balance in allergic rhinitis

Objective: To explore the expression and significance in regulating immune balance of programmed cell death protein 1 (PD-1) and its ligands PD-L1, PD-L2 in allergic rhinitis (AR). Methods: Eighty-two patients who received outpatient treatment due to high nasal reaction symptoms or were hospitalized due to nasal septum deviation and underwent nasal septum correction surgery in Department of Otorhinolaryngology Head and Neck Surgery of Renmin Hospital of Wuhan University from May 2018 to May 2019 were enrolled, including 42 males and 40 females, with the age ranging from 14 to 38 years old. Blood, inferior turbinate nasal mucosal tissue and relevant clinical data were collected. Patients were divided into AR group and control group due to clinical manifestation, skin prick test and detection of specific IgE (sIgE) in serum. Immunohistochemistry was used to detect the expression of PD-1 and its ligands in nasal mucosa of the two groups. Flow cytometry was used to detect the proportions of PD-1(+)CD4(+)T cells, PD-L1(+) myeloid dendritic cells (mDCs), PD-L2(+)mDCs and Th2 cells in peripheral blood of the two groups. The expression levels of total IgE, sPD-1, sPD-L1 and sPD-L2 in serum of the two groups were detected by ELISA. The measurement data of normal distribution or normal distribution after the logarithm conversion to Ln were compared by t test. Pearson correlation or Spearman correlation was used to analyze the correlation among the indicators. P<0.05 was considered statistically significant. Results: The expression of PD-1 and its ligands on the surface of immune cells in the nasal mucosa of the AR group was significantly higher than that of the control group. The ratio of PD-1(+)CD4(+)T cells, PD-L1(+)mDCs and Th2 cells in peripheral blood of AR group was significantly higher than that of the control group ((15.24±6.45)% vs (8.71±5.33)%, (8.79±2.01)% vs (5.74±2.90)%, (7.89±1.95)% vs (2.52±1.34)%, all P<0.05). There was no significant difference in the ratio of PD-L2(+)mDCs between the two groups. Correlation analysis found that the proportion of PD-1(+)CD4(+) T cells was positively correlated with the Visual Analogue Scale (VAS) score of AR, total IgE concentration and the serum sIgE concentration (r value was 0.501, 0.541, 0.608, respectively, all P<0.05). The proportion of PD-L1(+)mDCs was positively correlated with the VAS score of AR and the serum sIgE concentration (r value was 0.604, 0.563, respectively, all P<0.05). The proportion of Th2 cells in peripheral blood was positively correlated with the proportion of PD-L1(+)mDCs and PD-1(+)CD4(+)T cells (r value was 0.538, 0.623, respectively, all P<0.05). Serum total IgE, sPD-1 and sPD-L1 in the AR group were significantly higher than those in the control group ((6.34±1.38) ng/ml vs (4.89±1.10) ng/ml, (4.40±1.01) pg/ml vs (3.79±1.21) pg/ml, (3.88±0.25) pg/ml vs (3.57±0.23) pg/ml, all P<0.05), and there was no significant difference in sPD-L2 levels between the two groups. Correlation analysis showed that sPD-L1 was positively correlated with total IgE and sIgE concentration (r values was 0.32, 0.45, respectively, all P<0.05). Conclusions: PD-1 and PD-L1 are highly expressed on the surface of immune cells in peripheral blood and nasal mucosa of AR patients, and sPD-1 and sPD-L1 expression levels in peripheral blood of AR patients are increased. The PD-1/PD-L1 signaling pathway promote AR inflammatory response by inducing Th2 type immune response.

Programmed cell death protein 1 and its ligands regulate immune balance in allergic rhinitis

Objective: To explore the expression and significance in regulating immune balance of programmed cell death protein 1 (PD-1) and its ligands PD-L1, PD-L2 in allergic rhinitis (AR). Methods: Eighty-two patients who received outpatient treatment due to high nasal reaction symptoms or were hospitalized due to nasal septum deviation and underwent nasal septum correction surgery in Department of Otorhinolaryngology Head and Neck Surgery of Renmin Hospital of Wuhan University from May 2018 to May 2019 were enrolled, including 42 males and 40 females, with the age ranging from 14 to 38 years old. Blood, inferior turbinate nasal mucosal tissue and relevant clinical data were collected. Patients were divided into AR group and control group due to clinical manifestation, skin prick test and detection of specific IgE (sIgE) in serum. Immunohistochemistry was used to detect the expression of PD-1 and its ligands in nasal mucosa of the two groups. Flow cytometry was used to detect the proportions of PD-1(+)CD4(+)T cells, PD-L1(+) myeloid dendritic cells (mDCs), PD-L2(+)mDCs and Th2 cells in peripheral blood of the two groups. The expression levels of total IgE, sPD-1, sPD-L1 and sPD-L2 in serum of the two groups were detected by ELISA. The measurement data of normal distribution or normal distribution after the logarithm conversion to Ln were compared by t test. Pearson correlation or Spearman correlation was used to analyze the correlation among the indicators. P<0.05 was considered statistically significant. Results: The expression of PD-1 and its ligands on the surface of immune cells in the nasal mucosa of the AR group was significantly higher than that of the control group. The ratio of PD-1(+)CD4(+)T cells, PD-L1(+)mDCs and Th2 cells in peripheral blood of AR group was significantly higher than that of the control group ((15.24±6.45)% vs (8.71±5.33)%, (8.79±2.01)% vs (5.74±2.90)%, (7.89±1.95)% vs (2.52±1.34)%, all P<0.05). There was no significant difference in the ratio of PD-L2(+)mDCs between the two groups. Correlation analysis found that the proportion of PD-1(+)CD4(+) T cells was positively correlated with the Visual Analogue Scale (VAS) score of AR, total IgE concentration and the serum sIgE concentration (r value was 0.501, 0.541, 0.608, respectively, all P<0.05). The proportion of PD-L1(+)mDCs was positively correlated with the VAS score of AR and the serum sIgE concentration (r value was 0.604, 0.563, respectively, all P<0.05). The proportion of Th2 cells in peripheral blood was positively correlated with the proportion of PD-L1(+)mDCs and PD-1(+)CD4(+)T cells (r value was 0.538, 0.623, respectively, all P<0.05). Serum total IgE, sPD-1 and sPD-L1 in the AR group were significantly higher than those in the control group ((6.34±1.38) ng/ml vs (4.89±1.10) ng/ml, (4.40±1.01) pg/ml vs (3.79±1.21) pg/ml, (3.88±0.25) pg/ml vs (3.57±0.23) pg/ml, all P<0.05), and there was no significant difference in sPD-L2 levels between the two groups. Correlation analysis showed that sPD-L1 was positively correlated with total IgE and sIgE concentration (r values was 0.32, 0.45, respectively, all P<0.05). Conclusions: PD-1 and PD-L1 are highly expressed on the surface of immune cells in peripheral blood and nasal mucosa of AR patients, and sPD-1 and sPD-L1 expression levels in peripheral blood of AR patients are increased. The PD-1/PD-L1 signaling pathway promote AR inflammatory response by inducing Th2 type immune response.

Small molecule inhibitors targeting the PD-1/PD-L1 signaling pathway.

Tumor cells form immune escape and subsequently obtain unlimited proliferation ability due to the abnormal immune surveillance mediated by immune checkpoints. Among this class of immune checkpoints, PD-1/PD-L1 was recognized as an anticancer drug target for many years, and so far, several monoclonal antibodies have achieved encouraging outcome in cancer treatment by targeting the PD-1/PD-L1 signaling pathway. Due to the inherent limitations of antibodies, the development of small molecule inhibitors based on PD-1/PD-L1 signaling pathway is gradually reviving in decades. In this review, we summarized a number of small molecule inhibitors based on three different therapeutic approaches interfering PD-1/PD-L1 signaling pathway: (1) blocking direct interaction between PD-1 and PD-L1; (2) inhibiting transcription and translation of PD-L1; and (3) promoting degradation of PD-L1 protein. The development of these small molecule inhibitors opens a new avenue for tumor immunotherapy based on PD-1/PD-L1 signaling pathway.

Current Understanding of the Mechanisms Underlying Immune Evasion From PD-1/PD-L1 Immune Checkpoint Blockade in Head and Neck Cancer.

Starting in 2014, large phase III clinical trials began to disclose the study results of using programmed death (PD)-1 immune checkpoint inhibitors (ICIs) (pembrolizumab, nivolumab) and PD-ligand (L)1 (atezolizumab, durvalumab, avelumab) ICIs immunotherapy in patients with advanced head and neck squamous cell carcinoma (HNSCC). In the recurrent and metastatic (R/M), cisplatin-refractory setting, nivolumab achieved a 2.2-fold increase of the median 1-year overall survival as compared with investigators' choice of salvage chemotherapy (36.0 vs. 16.6%). A paradigm shift to the winning regimen, pembrolizumab combined with platinum and infusional fluorouracil, has outperformed the past gold standard of cetuximab-based platinum and fluorouracil combination in terms of overall survival (median, 13.6 vs. 10.1 mo) when administered as the first-line treatment for R/M HNSCC. Nevertheless, many patients still did not respond to the PD-1/PD-L1 checkpoint inhibitor treatment, indicating innate, adapted, or quickly acquired resistance to the immunotherapy. The mechanisms of resistance to ICIs targeting the PD-1/PD-L1 signaling pathway in the context of HNSCC are the focus of this review. The past 5 years have seen improved understanding of the mechanisms underlying checkpoint inhibition resistance in tumor cells, such as: tumor cell adaption with malfunction of the antigen-presenting machinery via class I human leukocyte antigen (HLA), reintroduction of cyclin D–cyclin-dependent kinase (CDK) 4 complex to cell cycles, enrichment of CD44+ cancer stem-like cells, or development of inactivating mutation in IKZF1 gene; impairment of T-cell functions and proliferation through mutations in the interferon-γ-regulating genes, suppression of the stimulator of interferon genes (STING) pathway, or resulted from constitutional nutritional iron deficiency state; metabolic reprogramming by cancer cells with changes in metabolites such as GTP cyclohydrolase 1, tetrahydrobiopterin, kynurenine, indoleamine 2,3-dioxygenase, and arginase 1; defective dendritic cells, CD-69 sufficient state; and the upregulation or activation of the alternative immune checkpoints, including lymphocyte activation gene-3 (LAG3), T-cell immunoglobulin and ITIM domain (TIGIT)/CD155 pathway, T-cell immunoglobulin mucin-3 (TIM-3), and V domain-containing Ig suppressor of T-cell activation (VISTA). Several potential biomarkers or biosignatures, which could predict the response or resistance to the PD-1/PD-L1 checkpoint immunotherapy, are also discussed.

Ингибирование контрольных точек иммунитета при раке яичников

Immune checkpoints such as CTLA4 and PD1 and PD2 have significant impact on the immune response through T-cell function modulation. Tumor cells can use this mechanism to avoid immune surveillance through PD-L1 signaling pathway. Currently, the number of tumor immunotherapies is growing, including the application of anti-PDl and anti- PDLl monoclonal antibodies for specific immune response reactivation. Assessment of PD-L1 expression can be used as a potential prognostic biomarker for the efficacy of malignant tumor treatment and its duration as well as an immunotherapy-modulated response predictor. In the field of immunotherapeutic treatment of ovarian cancer, a number of questions remain unclear: how exactly does the pathological immune response develop when these tumors occur, how to identify the most promising tumors for exposure to anti-PDL1 and anti-PDL2 antibodies, which systems to use for the expression of molecules in tissues, which combination drugs with the inclusion of immunotherapy will be most effective and many others. The review provides information already obtained in the search for answers to these questions, and outlines the range of those studies that have yet to be carried out. Keywords: PD-1, PD-L1, immune checkpoints, cancer immunotherapy

Co-inhibition of BET proteins and PD-L1 as a potential therapy for OSCC through synergistic inhibition of FOXM1 and PD-L1 expressions.

Bromodomain and extra-terminal domain (BET) proteins are important epigenetic regulators that facilitate the transcription of genes in chromatin areas linked to acetylated histones. JQ1, a BET inhibitor (BETi), has anti-proliferative and apoptosis activity against many cancers including oral squamous cell carcinoma (OSCC). In this research, we investigated the mechanism underlying the effects of JQ1 in OSCC and investigated strategies to increase its therapeutic potential. The OSCC Cal27 and SCC25 cell lines were used for in vitro experiments. Cells were treated with JQ1 and/or siRNA targeting PD-L1 (siPD-L1), and cell viability, apoptosis, and cell cycle were evaluated by cell proliferation assay, colony formation assay, apoptosis, and cell cycle analysis. Levels of cleaved caspase-3, p53, BRD4, PD-L1, and FOXM1 were determined by quantitative real-time PCR and Western blot. The effects of single inhibitor or combination inhibitor treatment on tumors derived from Cal27 cells in mice were monitored. FOXM1 and PD-L1 were downregulated by JQ-1 in a dose-dependent manner. Combined JQ1 and siPD-L1 treatment synergistically inhibited cell growth and induced apoptosis and cell cycle arrest in vitro and synergistically inhibited tumor growth in vivo compared with single treatments. The combination treatment also synergistically suppressed FOXM1 and PD-L1 signaling pathways in OSCC cells. Our research suggests that FOXM1 and PD-L1 are targets of BETi in OSCC cells and indicate that combining PD-L1 blockade with BETi may be a useful therapeutic approach in OSCC through further suppressing FOXM1 and PD-L1.

Progress in research on tumor immune PD-1/PD-L1 signaling pathway in malignant bone tumors

Programmed death receptor 1 (PD-1) and its ligand PD-L1 have been shown to play an important role in evading the immune system. In recent years, PD-1/PD-L1 blockade has shown significant clinical effects in many malignancies, including malignant melanoma, renal cell carcinoma, classic Hodgkin lymphoma, non-small cell lung cancer and so on. PD-1/PD-L1 signaling pathway has become a new target of immunotherapy in patients with malignant tumors. However, there are few researches on immunotherapy in malignant bone tumors, and the progress of clinical research on PD-1/PD-L1 remains to be elucidated. This review started from the mechanism of PD-1/PD-L1 signaling in tumor immunity, and analyzed the application prospect of PD-1/PD-L1 antibodies in malignant bone tumors. We hope to provide a theoretical basis for the treatment of malignant bone tumors based on PD-1/PD-L1 signaling pathway in China.

Patient-Derived Non-Muscular Invasive Bladder Cancer Xenografts of Main Molecular Subtypes of the Tumor for Anti-Pd-l1 Treatment Assessment.

Background: Establishment of heterotopic patient-derived xenografts of primary and relapsed non-muscular invasive bladder cancer (NMIBC) to explore the biological property of PD-L1 signaling that may impact bladder tumor growth in humanized animals. Methods: Tumor cells of luminal, basal, and p53 subtypes of primary and relapsed NMIBC were engrafted to irradiated (3.5 Gy) NOG/SCID female mice along with intraperitoneal transplantation of human lymphocytes (5 × 107 cells/mouse); a role of PD-L1 signaling pathway inhibition for bladder cancer growth was assessed in humanized animals that carried PD-L1-expressing main molecular subtypes of bladder carcinoma patient-derived xenografts (PDX) and provided with selective anti-PD-L1 treatment. We used two-tailed Student’s t test to explore differences between main and control subgroups. Significance of intergroup comparison was measured with one-way ANOVA followed by the Tukey’s or Newman–Keul’s criterion. Survival curves were analyzed with the Gehan’s criterion with the Yate’s correction. The Spearman’s correlation was used to assess the link between CD8+ expression and sPD-L1 serum level. Differences were considered statistically significant at p < 0.05. Results: Heterotopic primary and relapsed luminal, basal, and p53 subtypes of NMIBC PDXs were established. More than 25% of counted tumor cells of all PDX specimens expressed PD-L1, so the tumors were ranged as PD-L1 positive. Anti-PD-L1 intervention increased survival of the animals that carried both primary and relapsed luminal noninvasive, muscular invasive, and relapsed luminal bladder cancer xenografts. There was significant retardation of tumor volume duplication time in aforementioned subgroups correlated with PD-L1 expression. Bad response of p53 mutant subtypes of NMIBC on specific anti-PD-L1 treatment may be associated with low CD8+ cells representation into the tumors tissue. Conclusions: Established PD-L1-positive NMIBC PDXs differently replied on anti-PD-L1 treatment due to both NMIBC molecular subtype and tumor T-suppressors population. The results may have major implications for further clinical investigations.