| The character of tumor cell which is different from normal cell rests with its continuous self replication and obstinate anti-differentiation and apoptosis. The deregulation of cell proliferation is the essential issue for the tumorigenesis,which is closely associated with the disturbance of cell cycle control. In this paper, we investigated the effect of the key moleculars in Gl phase on the cell proliferation, differentiation and apoptosis of heamatological tumor cell and hematopoietic stem/progenitor cells.In the first section of paper, we established the model of tumor cell proliferation ,differentiation, apoptosis by HMBA to study the change of Cyclin D, cyclin E,p27 and related genes such as c-myc.RKBcl-2 and their significances. After 72 hours' treatment of HMBA on HL-60 and U937 cells , the rates of CD11b expression of both cell lines significantly increased ( for example, the rates of CD11b were 69.90?5.02%. 46.41?7.80% in 4mM HMBA group for HL-60 and U937 cells, respectively);high dose of HMBA could induce the increased Annexin-V expression( the rates were 8.90 ?0.81 %, 11.23?5.57%,respectively); at the same time, the most cells of HL-60 and U937 were retained in Gl phase by cell cycle distribution analysis.In this kind of cell model, we found the significantly increased Cyclin D, p27 expression( for example, the rate of Cyclin D expression was 63.00 ?13.55%,p27 67.65 ?10.49% in HL-60 cells treated by 4mMHMBA) and reduced Cyclin E expression( the rate of Cyclin E was 1.33 ?0.23 % in HL-60 cells treated by 4mMHMBA). All of these results presented in dose dependent manner. Because of the closed association of cell proliferation, differentiation and apoptosis, the Cyclin E , a positive regulator for cell cycle, and p27, a negative regulator for cell cycle, might play a important role in this cell model. The mRNA levels of c-myc and Bcl-2 reduced significantly in both HL-60 and U937 cells treated by HMBA, and Rb mRNA increased significantly in HL-60 cells but not in U937 cells, suggesting related gene expressions was also involved in cells model established in our paper. This part results indicated that Cyclin E and p27 were mightly involved in the mechanisms of leukemic cell proliferation. differentiation and apoptosis. Thus, down-regulation Cyclin E and up-regulation p27 might provide the new strategy for inhibiting tumor cell proliferation and promoting its differentiation and apoptosis.In the second part, The gene transfection of p27 gene was performed into tumor cell in order to testify its effects on cell proliferation, differentiation and apoptosis.We successfully constructed the p27 expression plasmid (pEGFP-Cl/hp27), and applied this plasmid and adenovirus packing p27 gene (Advp27) to transfect and infect HL-60 and Raji cells, respectively. The efficiency of pEGFP-Cl/hp27 by electrophoration was 31.9%, and AdLac Z's were 40.3 %, 32 % for HL-60 and Raji cells, respectively. RT-PCR showed the significant expression of p27 mRNA and protein. The transduction of p27 gene into HL-60 and Raji cells could significantly inhibit cell growth and proliferation ,and induced increased expression of CD 11 b(for example, at 72hours, the rate of GDI Ib expression was 27.9?.1 % in HL-60 cells transfected by pEGFP-Cl/hp27 and 33.8?.1 % by Adp27 infection). Adp27 induced significant cellapoptosis in HL-60 and Raji cells(for example, the rates of Annexin V+P\ cell were 46.9?.5% and 35.7?1.2% for HL-60 and Raji cells, respectively after 72 hours'infection). The results indicated p27 gene significantly inhibited tumor cell proliferation, and promote significantly cell differentiation and apoptosis , which suggesting p27 played a very role in the cell proliferation, differentiation and apoptosis. This part results may provide the foundation for gene therapy of hematological tumor by using p27 gene.In the third section of paper, we blocked the expression of CDK2 gene which located in the core position of cell cycle progression. CDK2 SiRNA plasmid (pBS/U6/CDK2) was trasducted into HL-60 cells by electrophoration , a...
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