维生素E琥珀酸酯增强DR5抗体对Raji和K562细胞的凋亡作用(英文)

Objective: The aim of our study was to detect whether Vitamin E Succinic Acid (VES) could regulate the expression level of DR5 in the cells and further elucidate the potential mechanisms involving that VES enhances the effect of mDRA-6 to eradicate leukemia Raji and K562 cells. Methods: MTT method was used to detect the growth inhibition of VES and mDRA-6 to Raji and K562 cells. Annexin V-FITC/PI double staining assay was used to analysis the apoptosis of leukemia cell. Flow cytometry was used to detect the cell surface DR5 expression. Immunoblotting technique was used to detect the DR5 protein expression. Results: MTT detection showed that 10 μmol/L mDRA-6 on the cell death rates of Raji and K562 cells were 21.98% and 5.23%, respectively. While increasing concentration of VES (5 μmol/L, 10 μmol/L, 20 μmol/L) and mDRA-6 both on the cell viability of Raji or K562 cells, the mortality of Raji cells elevated to 24.67%, 35.65% (P<0.01) and 40.22% (P<0.01), respectively. Similarly, the mortality of K562 cells increase to 6%, 7.89% (P<0.01) and 8.67% (P<0.01), respectively. To further specify the increased cell death rate induced by mDRA-6 and VES, the treated cells were analyzed by Annexin-V/PI staining assay. As shown in Fig. 1, the apoptosis rates of Raji and K562 cells treated with 2 μg/mL mDRA-6 for 12 h were 20.79% and 7.74%. Compared with this, the proportion of apoptotic cells increased upon exposure to 2 μg/mL mDRA-6 combination with 10 μmol/L VES, the apoptosis rates of Raji and K562 cells were 43.18% and 16.99%, respectively. To examine the anticancer effects of a combination strategy based on mDRA-6 and VES. We analyzed whether VES could elevated the expression level of DR5 on Raji and K562 cytomembrane by FACS. Interestingly, after treated with 10 μmol/L VES for 12 h, the expression level of DR5 on Raji and K562 cell surface increased from 50.66% to 70.08%, and 15.02% to 16.38%, respectively. Immune imprinting technology test showed that, different concentrations of VES could increase Raji and K562 cell DR5 protein expression. Conclusion: VES enhances the effect of mDRA-6 to eradicate leukemia Raji and K562 cells. The proper mechanism is VES could enhance the Raji and K562 cell membrane expression of DR5, and VES can also enhance the DR5 protein expression of cells.

High-Affinity Decoy PD-1 Mutant Screened from an Epitope-Specific Cell Library

Immunotherapy with anti-programmed cell death protein-1(PD-1)/programmed cell death ligand-1(PDL1)monoclonal antibodies has become routine in the treatment of many kinds of human cancers,such as lung cancer,intestinal cancer,and melanoma.The PD-1/PD-L1 pathway inhibits T cell activation in the micro-environment,making it an attractive target against cancer.Wild-type(WT)PD-1 ectodomain has been shown to have difficulty blocking PD-1/PD-L1 mixture formation due to its low affinity.The present work uses three-dimensional(3D)crystal complex structures to analyze the interaction by which PD-1 binds to PD-L1 or PD-L2.It also reports on a theoretical study of the binding mode between PD-1 and its clinical antibody Opdivo.Based on the theoretical binding analysis of PD-1 and its ligands(i.e.,PD-L1 and PD-L2)or antibody(Opdivo),a small-content,epitope-oriented mammalian cell library was established for PD-1.After three rounds of cell sorting,the decoy PD-1 mutant 463,which presented a higher affinity than WT PD-1 to the PD-L1(the affinity has increased by almost three orders of magnitude)was screened out.It exhibited an inhibitory effect against PD-1 to prevent it from forming mixtures with PD-L1,which was similar to the effect of the commercial anti-PD-L1 antibody atezolizumab(ATE).The median effective concentration(EC50)value of the decoy mutant was 0.031 μg·mL^(-1) in comparison with 0.063 μg·mL^(-1) for ATE;both values were much lower than that of WT PD-1,at 2.571 μg·mL^(-1).The 463 decoy mutant reversed the inhibitory function of PD-1 in T cell activation;furthermore,10 mg·kg^(-1) of 463 inhibited about 75%of tumor growth in vivo in a MC38 transgenic xenograft mice model,which was similar to the activity of ATE.More interestingly,an even lower dose of 463(2 mg·kg^(-1))showed a better effect than 10 mg·kg^(-1) of WT PD-1.This work offers the decoy 463 with an improved curative effect,which holds potential to become a good option against PD-1/PD-L1-related cancers.

mDRA-6与尼美舒利对人肝癌细胞系SMMC-7721细胞的协同杀伤效应(英文)

Objective: The aim of this work was to evaluate anti-tumor effects of mDRA-6 plus nimesulide on a human hepatocellular cancer cell line, SMMC-7721, and study the main mechanisms. Methods: The DR5 receptor of SMMC-7721 cells was detected by flow cytometry (FCM). For further experimental application, SMMC-7721 cells were treated with proper dose of mDRA-6, nimesulide, or mDRA-6 plus 200 μmol/L nimesulide; untreated SMMC-7721 cells were comparably set as control. Cytotoxicity was tested by MTT assay; cell morphology was examined using Hoechst 33258 staining; and apoptosis was determined by FCM. Results: The positive rate of DR5 on SMMC-7721 was 95.0%. Either mDRA-6 or nimesulide alone induces SMMC-7721 cell death in a dose-dependent manner. Treatment of 1,600 ng/mL mDRA-6 for 12h led to a cell-death rate of 35.0%, while an increased cell-death rate (91.1%) was found under the same condition of mDRA-6 treatment supple- mented with 200 μmol/L nimesulide. Hoechst 33258 and Annexin V/PI staining confirmed apoptosis as the main cause of this anti-tumor response. Conclusion: Both mDRA-6 and nimesulide can induce apoptosis of SMMC-7721 cells, and they have synergistic anti-tumor activities against SMMC-7721.

cAMP Modulates Macrophage Development by Suppressing M-CSF-Induced MAPKs Activation

M-CSF is a key cytokine in macrophage development by inducing MAPKs activation, and cAMP can inhibit MAPKs activation induced by inflammatory stimuli. To explore the effects of cAMP on M-CSF-induced MAPKs activation and on macrophage development, the model of bone marrow-derived murine macrophages （BMMs） was used. The effects of cAMP on M-CSF-induced MAPKs activation were analyzed by Western blotting assay, and the effects of cAMP on CD14 and F4/80 expression during macrophage development were examined by FACS analysis. Macrophage morphology showed the successful establishment of the model of macrophage development. Western blotting assay revealed that M-CSF activated ERK, JNK and p38 in both mature and immature macrophages, and cAMP inhibited M-CSF-induced ERK, JNK and p38 activation in a time-dependent manner. FACS analysis revealed that macrophage development was impaired with cAMP pretreatment. In conclusion, cAMP modulates macrophage development by suppressing M-CSF-induced MAPKs activation. Cellular ＆ Molecular Immunology.

Inhibitory activity of Bifidobacterium adolescent combined with cisplatin on melanoma in mice and its mechanism

The aim of this study is to explore inhibitory activity of Bifidobacterium adolescent combined with cis-platin on the growth of melanoma(B16)in mice and the underlying mechanism.C57 mice were inoculated with B16 cancer cells to construct mouse model of melanoma and treated with bifidobacterium adolescent combined with cisplatin.Ratios of inhibitory activity on the growth of melanoma(B16)were calculated.Pathology changes of the tumor were observed by HE staining.B16 cell cycles were examined on a flow cytometer.Lymphocyte prolif-eration was measured with MTT assay and the T-cell sub-set was measured by double marked fluorescence.When bifidobacterium of 1010 cfu/L was injected,the ratio of inhibitory activity on the growth of melanoma(B16)reached 54%,which was similar to that of cisplatin group.The ratio of inhibitory activity reached 74.45%when the mice were treated by bifidobacterium combined with cis-platin.HE staining shows that bifidobacterium inhibited B16 cell proliferation and enhanced the cisplatin`s killing activity on B16 cells.The results of flow cytometry demonstrated that B16 cell proliferation was arrested at G1 stage after treatment with bifidobacterium.The B16 cell proliferation was arrested at S stage after treatment with cisplatin.The CD4+percentage increased and the difference was significant compared with the normal group after treatment with bifidobacterium,indicating that T-cell immune activity was enhanced.Treatment with bifidobacterium combined with cisplatin can enhance the inhibitory activity on the growth of melanoma(B16)of cisplatin.The mechanism of the inhibitory activity on B16 cell proliferation is correlated with the enhanced immune activity in mice.

Characterization of a Novel Anti-DR5 Monoclonal Antibody WD1 with the Potential to Induce Tumor Cell Apoptosis

TNF-related apoptosis-inducing ligand （TRAIL） is a TNF family member capable of inducing apoptosis. Death receptor 5 （DR 5） is a key receptor of TRAIL and plays an important role in TRAIL-induced apoptosis. To prepare monoclonal antibodies （mAbs） against DR5, cDNA encoding soluble DR5 （sDR5） was firstly amplified by reverse transcriptase-polymerase chain reaction （RT-PCR） with specific primers, and then inserted into a prokaryotic expression vector pET-30a. The recombinant plasmid was expressed in Escherichia coli strain BL21 （DE3）, and sDR5 was purified by nickel affinity chromatography. As an antigen, sDR5 was used to immunize mice. Hybridomas secreting antibodies against sDR5 were identified. One positive done was selected to produce antibody, WD1. ELISA and immunofluorescence demonstrated that WD1 could bind recombinant sDR5 and membranebound DR5 （mDR5） on Jurkat and Molt-4 cells. ATPLite assays showed that Jurkat and Molt-4 cells were sensitive to the antibody in a dose dependent manner. The Annexin V/PI assays and Giemsa＇s staining both showed that WD1 could induce Jurkat cell apoptosis efficiently. Transient transfection of 293T cells and indirect immunofluorescence assay demonstrated that mAb （WD1） couldn＇t cross-react with DR4. Our findings indicated that the novel antibody, WD1 could act as a direct agonist, bind DR5 characteristically, and initiate efficient apoptotic signaling and tumor regression. Thus, WD1 would be a leading candidate for potential cancer therapeutics. Cellular ＆ Molecular Immunology.

Functional Identification of the Stable Transfection C5aR Cell Line Molt-4

The complement C5 anaphylatoxin receptor is a member of the seven transmembrane-spanning G protein-coupled receptor superfamily that signals through Gcxi and Gtz16. C5aR is mostly expressed on neutrophils, macrophages and endothelial cells. C5a and C5aR interaction plays an important role in numerous biological effects such as in vivo cytokine storm which results in inflammatory damage. Considering the limitation of collection of human peripheral blood neutrophils and their short half life, the stably transfected cell line for studying the biological effects of C5aR is needed. In this study, we transfected C5aR gene into Molt-4 cell line and examined the function of ectopic C5aR. Our results showed stable expression of the C5aR in Molt-4 cell line and their interaction with human C5a induced ERKI/2 phosphorylation, Ca＋＋ influx. This stable transfected cell line may provide a useful tool for studying signal pathways related to C5a and C5aR interplay and antibody development specific for C5aR. Cellular ＆ Molecular Immunology.