ABSTRACT
Objective: To investigate the effects of miR-200a on the proliferation of lung cancer cells and to identify its direct target genes. Methods:Real-time PCR was performed to analyze the miR-200a expression in 15 paired clinical specimens of non-small cell lung cancer and adjacent noncancerous tissues, human lung cancer cell lines (A549, NCI-H520, and SK-MES-1), and one human normal lung bronchial epithelial cell line (16HBE). The effects of miR-200a on the proliferation of A549 lung cancer cells were detected through CCK-8 method. The candidate target genes of miR-200a were identified by bioinformatics screening and then verified by dual luciferase reporter gene assay, real-time PCR, and Western blot. The effects of YAP1 downregulation on the proliferation of A549 lung cancer cell line were also observed through CCK-8 method. Results:The miR-200a expression in non-small cell lung cancer tissues and lung cancer cell lines was significantly decreased (P<0.01). The upregulation of miR-200a expression could significantly inhibit the pro-liferation of A549 lung cancer cells (P<0.01). Dual luciferase reporter gene indicated that miR-200a could directly affect the 3′-untrans-lated region of the YAP1 gene to inhibit luciferase activity (P<0.01). Real-time PCR and Western blot revealed that the upregulation of miR-200a expression could significantly reduce the mRNA and protein expression levels of YAP1 in A549 lung cancer cells (P<0.01). CCK-8 method indicated that the downregulation of YAP1 could significantly prevent the proliferation of A549 lung cancer cells (P<0.01). Conclusion:MiR-200a inhibits the proliferation of lung cancer cells by targeting YAP1. Thus, miR-200a elicits tumor suppression effects.
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Objective Delayed xenograft rejection (DXR) is a major barrier to the long-term xenograft survial.This study evaluated the interaction between human peripheral blood mononuelear cells (PBMC) and porcine endothelial cells (PEC),and the effects of new generation of rabbit antihuman leukocyte polyclonal antibody (newRALG) inhibiting xenogeneic cell-mediated immune responses.Methods newRALG was obtained from rabbits after immunization with activated lymphocytes and monoeytes.PEC were isolated from aorta,and human PBMC were isolated from peripheral blood.Co-cultures of PKH-26 labeled PEC with PBMC were established,newRALG,thymoglobulin,isotype Ig and scavenger receptor (SR) ligand poly G were added into the co-cultures.Cells were collected,then FACS analysis was carried out to detect the up-take of PEC membrane by monocytes and the expression of costimulatory molecules.Lymphocyte proliferative responses to PEC with or without antibody were evaluated by a xenogeneie mixed lymphocyte-endothelial cell reaction (xMLER).Results FACS analysis revealed that monocytes from PBMC-PEC co-cultures became positive for PKH-26 following their interaction with PKH-26 labeled PEC,indicating that they engulfed PEC membranes during activation.PKH-26 positive monocytes up-regulated the CD40 and CD80 expression.Furthermore,SR blockade with poly-G prevented PEC membrane up-take by monocytes,newRALG greatly reduced SR-mediated PEC membrane up-take.The effects of thymoglobulin in inhibiting PEC membrane uptake were limited.xMLER demonstrated strong lymphocyte proliferation in response to PEC,and lymphocyte proliferation was dramatically inhibited by newRALG but not isotype Ig at a dosmdependent manner.Conclusions Monocytes play an important role in xenogeneic immune responses.SR ligand poly G inhibits PEC membrane up-take.newRALG inhibits PEC membrane up-take by monocytes,suggesting that newRALG blocks SR.Additionally,newRALG inhibits lymphocyte proliferation in response to PEC.These results suggest that this new polyclonal preparation may thus impair the initiation of xeno-specific immune responses and prevent xenograft rejection.
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Objective To explore the expression and the role of monocyte-derived costimulatory molecuels during xenogeneic immune responses. Methods Porcine endothelial cells (PEC) were isolated from aorta, and subcultures were performed. CD4+ cells and monocytes were purified from human peripheral blood mononuclear cells (PBMC). PBMC-PEC co-cultures were established, and the cells were collected followed by staining with florescent-labeled monoclonal antibodies and analyzing by FACS. In selected experiments, monoclonal antibodies specific for CD154, CD80 and CD86 were added into PBMC-PEC co-cultures, and the effects of co-stimulatory molecule blockade in inhibiting lymphocyte proliferation in response to PEC were determined by 3H-thymidine up-take. The proliferation of CD4+ cells induced by PEC-conditioned monocytes with or without co-stimulation blockade was evaluated. Results PBMC-PEC co-incubation demonstrated dramatic lymphocyte proliferation as determined by 3H-thymidine up-take. FACS found that resting monocytes expressed only CD86 but not CD40 and CD80. CD14+ monocytes from PEC-stimulated PBMC demonstrated up-regulation of CD80 and CD40 expression. The up-regulation of CD86 was revealed. PEC-activated monocytes induced CD4+ cell proliferation while resting monocytes did not and this proliferation was inhibited by anti-CD154, anti-CD80 or anti-CD86 antibodies. Conclusions CD14+ monocytes play an important role during xenogeneie immune responses in indirect antigen presentation and co-stimulation- The interaction between monocyte-derived co-stimulatory molecules and CD4+ cell-derived CD154 and CD28 delivers secondary signal and induces CD4+ proliferation, and the co-stimulation blockade inhibits xe-nogeneic cell-mediated immune responses.
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Objective To investigate the immunological effects of thymoglobulin (RATG) on human CD4+and CD8+cells for costimulatory molecule gene expression and the production ofimmune-regulatory cytokines. Methods CD4+and CI8+T cells were isolated and purified fromnormal human peripheral blood mononuclear cells (PBMC) followed by incubation with RATG at37℃. Cells and culture supematants were collected at 24, 48, and 72 h after incubation, and analyzedby real-time quantitative polymerase chain reaction (RT-PCR) for CTLA-4, CD154, forkhead box P3(Foxp3), OX40, IFN-γ, IL-2, IL-10 and CD25 gene expression, and multiplex cytokine detectionassay for IFN-y, IL-2, IL-10, and IL-4 production. Untreated and rabbit isotype Ig-treated cells wereused as negative controls. Results RT-PCR demonstrated that RATG pre-treated CI+and CD8+cells upregulated the expression of CTLA-4, OX40, Foxp3, CD25, IFN-γ, IL-10 and IL-2 genes, anda dramatic increase of supernatant IFN-γ, IL-10, IL-2 and IL-4 was revealed 24 h after treatment asdetermined by multiplex cytokine detection assay when compared with negative controls. Theupre gulation of CTLA-4, Foxp3, OX40, IL-10 and CD25 was reduced, and a down-regulation ofCD154 and IL-2 gene expression was revealed 48 h after treatment. Cells, treated with RATG for 72h, demonstrated up-regulation of CTLA-4, Foxp3, OX40, IFN-y and CD25 gene expression, and theexpression of IL-2 and IL-10 genes was down-regulated. Additionally, supernatant IFN-γ, IL-2,IL-10 and IL-4 levels were decreased. Conclusion RATG stimulates CI4/CD8 T cells to up-regulatecostimulatory molecules and release immune regulation associated cytokines IF'N-γ, IL-2, IL-10in vitro. These results suggest that the unique effect of RATG on CD4+CD8+T cells may be animportant mechanism for its action in inducing immunoregulation, immunosuppression and transplanttolerance.