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@#Objective To construct a yeast two-hybrid recombinant bait plasmid of human programmed cell death ligand 1(PD-L1)immunoglobulin variable region(IgV)domain gene,detect its expression in yeast and detect the cytotoxicity and self-activation of PD-L1 IgV protein as well as the interaction between PD-L1 IgV and human thioredoxin(hTrx).Methods Human PD-L1 was analyzed by bioinformatics method,and primers were designed to amplify PD-L1 IgV domain based on the coding region of PD-L1 gene registered in NCBI GenBank database. PCR amplification was carried out with pENTERPD-L1 plasmid as template,and then cloned into yeast two-hybrid bait vector pGBKT7. The recombinant bait plasmid and pGBKT7 empty vector were transformed into Y2HGold yeast cells respectively,and the PD-L1 IgV gene and its expression were detected by PCR and Western blot;Meanwhile,the protein toxicity and self-activation of PD-L1 IgV were detected,and the interaction between PD-L1 IgV and hTrx was detected by drip plate method.Results The bioinformatics analysis results of PD-L1 were consistent with related reports. The recombinant bait plasmid pGBKT7-PD-L1 IgV was correctly constructed,and Y2HGold positive clone was obtained,in which PD-L1 IgV was stably expressed. The empty vector pGBKT7 and recombinant bait plasmid pGBKT7-PD-L1 IgV grew well on SD/-Trp and SD/-Trp/X-α-Gal plates with the same colony size and number and white colony,but they did not grow on SD/-Trp/X-α-Gal/AbA plates,which indicated that PD-L1 IgV protein had no toxicity and no self-activation effect on yeast. The results of drip plates test showed that all experimental groups grew well on SD/-Trp/-Leu plate,while only positive control group grew on SD/-Trp/-Leu/X-α-Gal/AbA plate and showed blue color,which indicated that bait protein PD-L1 IgV and hTrx did not self-activate,and there was no interaction between them.Conclusion Recombinant human PD-L1 IgV bait plasmid was successfully constructed. PD-L1 IgV protein showed no toxicity and self-activation effect on yeast cells,and there was no interaction between PD-L1 IgV and hTrx. Subsequently,hTrx can be used to construct a peptide aptamer library,from which peptide aptamers that specifically bind to PD-L1 IgV can be screened.
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@#Objective To prepare bispecific antibody targeting cluster of differentiation 73(CD73) and programmed cell death-ligand 1(PD-L1),and evaluate its binding ability and killing ability in vitro.Methods Using genetic engineering method,PD-L1 single-chain fragment variable(scFv) was inserted into the hinge region of CD73 monoclonal antibody to construct anti-CD73/PD-L1 bispecific antibody(BS-21),which was screened by CHO GS expression system to obtain highly expressed cell line.After purified by Protein A and molecular sieve,the purity of antibody was detected by size exclusion chromatography-high performance liquid chromatography(SEC-HPLC),the binding ability of antibody in vitro was detected by flow cytometry,and the killing ability in vitro was detected by using peripheral blood mononuclear cell(PBMC) to kill Calu 1 lung cancer cells in vitro.Results High-yield cell lines were obtained by pressure screening.A bispecific antibody BS-21 with a purity of 99.6% was obtained by purification,which bound to CD73 and PD-L1 molecules simultaneously.Compared with anti CD73 and anti PD-L1 groups,BS-21 group significantly increased the killing rate of immune cells to Calu 1 tumor cells(F=30.36,each P<0.001).Conclusion Bispecific antibody BS-21 reduced the immunosuppressive effect of CD73 and PD-Ll on immune cells simultaneously,and showed good anti-tumor function.
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@# Lung cancer is the most frequent cancer and the leading cause of cancer death all around the world. Anti-programmed cell death 1 (PD-1)/programmed cell death-ligand 1 (PD-L1) therapies have significantly improved the outcomes of non-small cell lung cancer (NSCLC) patients in recent years. However, the objective response rate in non-screened patients is only about 20%. It is very important to screen out the potential patients suitable for immunotherapy. Immunohistochemical staining of tumor tissue biopsies with PD-L1 antibodies can predict the therapeutic response to immunotherapy to some extent, but it still has some limitations. Recently some clinical studies have shown that PD-L1 expression in circulating tumor cells (CTC-PD-L1) is a potential independent biomarker and may provide important information for immunotherapy in NSCLC. This article will review technology for CTC-PD-L1 detection and the predictive value of CTC-PD-L1 for immunotherapy in NSCLC and review the latest clinical research progress.
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@#[Abstract] Objective: To investigate the changes in malignant biological behaviors and expression of programmed cell death-ligand 1 (PD-L1) in esophageal squamous cell carcinoma (ESCC) YES-2 cell line after cis-dichlorodiammine platinum (CDDP) induction (YES-2/CDDP-R). Methods: YES-2 cells were treated with CDDP from low concentration to high concentration (0.25-2.0 μg/ml) with intermittent impact (15-25 days per concentration) to establish ESCC CDDP-resistant cell line YES-2/CDDP-R. The morphological change of YES-2/CDDP-R cells was observed under the inverted microscope. Methyl thiazolyl tetrazolium (MTT) was used to detect cell sensitivity to CDDP. Wound healing assay was used to detect cell migration ability. qPCR and Western blotting were used to detect mRNA and protein expressions of PD-L1. Results: After CDDP gradien ttreatment for9 months,YES-2/CDDP-R cells were successfully established. The morphology of the YES-2/CDDP-R cells showed uneven size, intracellular vacuoles and significantly increased black particles along with the appearance of huge cells. The IC50 of CDDP for YES-2/CDDP-R cells was significantly higher than that for parental cells, indicating decreased sensitivity to CDDP (P<0.05). Compared to theYES-2 cells, the proliferation and migration of YES-2/CDDP-R cells were significantly increased (P<0.05 or P<0.01), and the mRNA and protein expressions of PD-L1 were significantly up-regulated (all P<0.001). Conclusion: YES-2 cells with CDDP resistance (YES-2/CDDP-R) were successfully established. The sensitivity of YES-2/CDDP-R cells to CDDP was significantly reduced while the abilities of cell proliferation and migration were enhanced. The up-regulation of PD-L1 in YES-2/CDDP-R cells suggests that CDDP-resistance could promote immune escape by inducing PD-L1 up-regulation.
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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.
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@# Objective: : To investigate the expressions of chemokine-like factor superfamily 6 (CMTM6) and programmed cell death ligand 1 (PD-L1) in glioma tissues and their correlation with clinicopathological features of patients. Methods： ：From January 2012 to December 2015, 86 brain glioma tissues and 30 brain tissues (Control group) from patients operated with decompressive of craniotomy were collected from the FifthAffiliated Hospital of Zhengzhou University. The distribution and expressions of CMTM6 and PD-L1 protein in brain glioma tissues were detected by immunohistochemistry and WB methods. The differential expression of CMTM6 and PDL1 between glioma tissues and normal brain tissues was analyzed by t test of two independent samples. Single variant χ2 test was used to analyze the relationship between the expression of CMTM6, PD-L1 and the clinicopathological features of patients. Results: The expression of CMTM6 in glioma tissues was significantly higher than that in control tissues (P<0.01). The expression levels of CMTM6 and PD-L1 in high pathological grade (WHO III-IV) glioma tissues were significantly higher than those in low pathological grade (WHO I-II) glioma tissues (all P<0.01). The expression of CMTM6 was correlated with pathological grade, dizziness history, epilepsy seizure and PD-L1 expression (all P<0.05), while the expression of PD-L1 was correlated with pathological grade, epilepsy seizure and CMTM6 expression (all P<0.05). Conclusion: There is a correlation between the expression of CMTM6 and PD-L1 in glioma tissues, both of which are highly expressed and are expected to be used to study glioma signaling pathways.
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Small-cell lung cancer (SCLC) has a high degree of malignancy and is characterized by strong invasiveness, rapid growth, and early metastasis. SCLC is sensitive to initial treatment with chemotherapy and radiotherapy, but it can easily relapse and has a poor prognosis. Both programmed death-1 (PD-1) and programmed cell death-ligand 1 (PD-L1) antagonists activate the immune response of tumor cells by activating T cells, and have shown exciting curative effects in clinical studies of SCLC, thereby becoming powerful po-tential agents to treat SCLC in the future. This article aims to illustrate the progress of PD-1/PD-L1 inhibitors in the treatment of SCLC, as well as the role of PD-L1 expression and tumor mutation burden (TMB) as a biomarker in SCLC.