The Effect Of DLL4 Gene On The Protein Expression Of YY1 And C-Myc In The Leukemia Cell Line K562 Cells And Cell Growth

Objective: This article adopts transfection technology of eukaryotic expression vector , transfect pBudCE4.1-dll4 into chronic myelogenous leukemia cell line K562 by Lipofectamine 2000, to observe the effects of Notch ligand DLL4 on YY1 protein ,c-Myc protein in K562 cells and the growth of K562 cells.To further study whether YY1 transcription factor is activated in Notch signaling pathway and the effects of DLL4 on the protein expression of proto-oncogene c-Myc and the growth of leukemic cells.Methods: This experiment is divided into three groups: normal control group, negative control group (transfected pBudCE4.1), experimental group (transfected pBudCE4.1-DLL4). Using lipofectamine 2000 transfect plasmid of each group into leukemia cells,â‘ 48 hours after transfection, the cells were collected with RIPA cell lysis buffer, the protein expression level of exogenous DLL4, YY1 and c-Myc in each group cells was detected by Western Blot;â‘¡48 hours after transfection, the cells were collected, using cell smear the protein expression level of YY1 and c-Myc was detected by indirect immunocytochemical method;â‘¢Adopted Cell Counting Kit-8 to detect OD Value of every group; 48-hours after transfection, the cells was detected by flow cytometry for cell cycle distribution and apoptosis.Results: With Lipofectamine 2000, each group plasmid was successfully transfected into leukemic cells in vitro. After 48 hours,â‘ the protein expression of exogenous DLL4, YY1 and c-Myc was detected by Westen bolt in K562 cells of every group; analyze the results with semi-quantitative analysis method by the Quantity 0ne software, Statistical analysis using SPSS statistical software for data processing, The protein expression lever of DLL4, YY1 and c-Myc of the experimental group cells was significantly more than control groups, p< 0.05, and it was statistically significant.â‘¡The protein expression of YY1 and c-Myc was detected by indirect immuno -cytochemistry. Using the rank sum test to compare protein expression level among three group. The protein expression of YY1 and c-Myc in the experimental group was significantly more than control groups, and p <0.05, it was statistically significant.â‘¢Make the growth curve of K562 cells in every group; 48 hours after transfection, K562 cells in every group were detected by flow cytometry, G0/G1 phase cells of the experimental group was increased than control groups, and p< 0.001, and the number of apoptotic cells were increased, p< 0.001,it was statistically significant.Conclusion: The recombinant plasmid pBudCE4.1-DLL4 transfected into leukemia cells in vitro increased the protein expression of DLL4, transcription factor YY1 and proto-oncogene c-Myc, made the growth speed of K562 cells in experiment group(transfected pBudCE4.1-DLL4 ) be slower than the others and induced cell cycle arrest in G0/G1 phase and apotosis. However, the increasing of c-Myc protein expression by DLL4 was not effective to the growth of K562 cells.