ABSTRACT
OBJECTIVE@#To investigate the effect of tumor necrosis factor death receptor (DR) 4 demethylation to the proliferation and apoptosis of myeloid leukemia K562 cells.@*METHODS@#The logarithmic phase of K562 cells were treated by desitabine (DCA) at 0, 0.8, 1.6 and 3.2 μmol/L, and the cells were divided into control group, DCA low dose group, DCA medium dose group and DCA high dose group respectively. The cells in control group were treated by tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) 0.5 μg/ml for 24 h, and the cells were divided into TRAIL group. The cells in DCA high dose group were treated by TRAIL 0.5 μg/ml for 24 h, and were divided into DCA high dose + TRAIL group. Methylation-specific polymerase chain reaction (MS-PCR) was used to measure the methylation status of the DR4 gene promoter in the control group and DCA low, medium and high dose groups. Real-time fluorescent quantitative polymerase chain reaction (qRT-PCR) and Western blot were used to determine the relative expression of DR4 mRNA and protein in the control group and DCA low, medium and high dose groups. Dime- thylthiazole (MTT) method was used to determine the inhibition rate of cell proliferation of the cells in control group, DCA high dose group, TRAIL group, DCA high dose + TRAIL group. Flow cytometry was used to determine the apoptotic rate of the cells in control group, DCA high dose group, TRAIL group, DCA high dose + TRAIL group.@*RESULTS@#The cells in the control group were methylation-positive, the brightness of the methylation bands of the cells in the DCA low, medium, and high dose groups was gradually decreased to disappear, and the DCA high dose group showed negative for methylation. The relative expression of DR4 mRNA and protein in the control group, DCA low, medium and high dose groups was increased sequentially (r=0.624, 0.704). The inhibition rate of cell proliferation of the cells in the control group, DCA high dose group, TRAIL group, DCA high dose + TRAIL group was increased sequentially (r=0.653, 0.754, 0.709, 0.725) at 24, 48 and 72 h.@*CONCLUSION@#DCA can reverse the methylation level of DR4 gene promoter in ML K562 cells and up-regulate the expression of DR4, which may enhance the proliferation inhibition and apoptosis promotion effects of TRAIL on K562 cells.
Subject(s)
Humans , Apoptosis , Cell Line, Tumor , Cell Proliferation , Demethylation , K562 Cells , Leukemia, Myeloid , Receptors, TNF-Related Apoptosis-Inducing Ligand/metabolism , TNF-Related Apoptosis-Inducing Ligand/metabolismABSTRACT
The study was aimed to investigate the effect of anti-mouse CD122 antibody on the hematopoietic repopulating capacity of cord blood CD34⁺ cells in a humanized murine model-non obese diabetic/severe combined immunodeficiency (NOD/SCID) mice. After sublethal irradiation with γ-ray, NOD/SCID mice were intraperitoneally injected with 200 µg mouse isotype control antibody or anti-mouse CD122 antibody. Human cord blood CD34⁺ cells or phosphate-buffered saline (PBS) were injected via the tail vein at 6-8 hours later. Cohort of the mice injected with anti-mice CD122 antibody or control antibody alone were sacrificed at different time point (at week 2, 3, and 4 weeks) after the injection, and the percentage of NK cells in the peripheral blood was analyzed by flow cytometry. To evaluate the effect of anti-mouse CD122 antibody on the repopulating capacity of cord blood CD34⁺ cells in the recipient mice, phenotype analysis was performed in the bone marrow at 6 and 8 weeks after the transplantation. The results showed that the proportion of NK cells in the peripheral blood were (4.6 ± 0.6)% and (5.7 ± 1.7)% at week 2 and 3 after anti-CD122 antibody injection respectively,which decreased by 60%, compared with the mice injected with isotype control antibody. After 6 and 8 weeks of cord blood CD34⁺ cell transplantation,the percentage of human CD45⁺ in the bone marrow of the recipient mice treated with anti-mice CD122 antibody was (63.0 ± 12.2)% and (53.2 ± 16.3)%,respectively,which were dramatically higher than that in the mice treated with isotype control antibody (7.7 ± 3.6)% and (6.1 ± 2.4)%. Moreover,at 8 weeks after transplantation,human CD34⁺ cells appeared significantly in the recipients treated with anti-CD122 antibody. It is concluded that the anti-mouse CD122 antibody enhances the hematopoietic repopulating capacity of cord blood CD34⁺ cells in the NOD/SCID mice through decreasing the proportion of NK cells.
Subject(s)
Animals , Humans , Mice , Antibodies , Allergy and Immunology , Antigens, CD34 , Bone Marrow , Cord Blood Stem Cell Transplantation , Fetal Blood , Allergy and Immunology , Hematopoietic Stem Cell Transplantation , Hematopoietic System , Cell Biology , Allergy and Immunology , Interleukin-2 Receptor beta Subunit , Allergy and Immunology , Killer Cells, Natural , Mice, Inbred NOD , Mice, SCID , Transplantation, HeterologousABSTRACT
ObjectiveTo establish the human periodontal ligament fibroblasts(HPDLFs)that express BMP2 and observe their biologicl characterization. MethodsA phagemid expression vector for BMP2 (pBK-B2) was transfected into HPDLFs by using LipofectAMINE. The BMP2 expression was determined by the immunohistochemical ABC method. The alkaline phosphatase (ALP) activity, osteocalcin (OC) production and capacity of mineralization were measured in the transfected cells. ResultsBMP2 protein was expressed in HPDLFs after gene transfection. The BMP2 gene transfected cells showed prominently elevated ALP activity, OC production and increase in mineralized nodules. ConclusionThe results indicate that BMP2 is expressed in HPDLFs and is involved in inducing differ- entiation of HPDLFs into osteoblast-like cells.