title: [Over-expression of DLL4/Notch1 ligand inhibits proliferation of K562 cells].
abstract: This study was aimed to explore the effect of DLL4/Notch1 ligand on cell growth in leukemia cell line K562 and its relevant mechanism. The pBudCE4.1-DLL4 plasmid was transfected into K562 cells by lipofectamine 2 000, RT-PCR and Western blot were applied to monitor the mRNA and the protein expression of exogenous DLL4 gene, as well as the expression of Notch1-ICD and target gene Hes1. Expression levels of Rb, YY1 and C-MYC protein in K562 cells were also detected by Western blot. Cell counting Kit-8 was used to detect the proliferation of K562 cells, and flow cytometry with Annexin V staining was used to detect the cell apoptosis. The results showed that the mRNA and protein expression levels of DLL4, Notch1-ICD and Hes1 in cells of experimental group were significantly higher than those of control groups (P < 0.05), indicating the successful activation of the Notch1 signaling pathway. The protein expression levels of Rb, YY1 and C-MYC in cells of experimental group significantly increased when compared with that of control group cells (P < 0.05). After transfection, the proliferation of K562 cells was obviously inhibited, and apoptosis rate in DLL4-transfected cells was significantly enhanced. DLL4 transfection significantly increased the number of cells in G1 phase and decreased that in S phase. It is concluded that the over-expression of DLL4 ligand gene in K562 cells results in successful activation of the Notch1 signaling pathway, increases expression of Rb, YY1 and C-MYC genes, which induces apoptosis and reduces proliferation.
authors.affiliation: Department of Hematology,The First Affiliated Hospital, Fujian Medical University, Fuzhou 350005, Fujian Province, China. E-mail: fjrhb@sina.com.
authors.forename: Hong-Bing
authors.initials: HB
authors.lastname: Rui
authors.affiliation: Department of Hematology,The First Affiliated Hospital, Fujian Medical University, Fuzhou 350005, Fujian Province, China.
authors.forename: Han-Hua
authors.initials: HH
authors.lastname: Zhang
authors.affiliation: Department of Hematology,The First Affiliated Hospital, Fujian Medical University, Fuzhou 350005, Fujian Province, China.
authors.forename: Li-Fang
authors.initials: LF
authors.lastname: Shi
authors.affiliation: Department of Hematology,The First Affiliated Hospital, Fujian Medical University, Fuzhou 350005, Fujian Province, China.
authors.forename: Zhi-Yong
authors.initials: ZY
authors.lastname: Ma
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D017209:Apoptosis; D002135:Calcium-Binding Proteins; D002453:Cell Cycle; D049109:Cell Proliferation; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000378:metabolism*; D020014:K562 Cells; D008024:Ligands; D010957:Plasmids; D016271:Proto-Oncogene Proteins c-myc; D012333:RNA, Messenger; D051881:Receptor, Notch1 / Q000378:metabolism*; D015398:Signal Transduction; D014162:Transfection
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D002135:Calcium-Binding Proteins; C424126:DLL4 protein, human; D036341:Intercellular Signaling Peptides and Proteins; D008024:Ligands; C497761:NOTCH1 protein, human; D016271:Proto-Oncogene Proteins c-myc; D012333:RNA, Messenger; D051881:Receptor, Notch1