The Expression Of TGF-β1 In Leukemia Cells And The Effects Of Extragenic TGF-β 1 Gene On High Tumorigenic HL-60 Cells

In physiological circumstance, the proliferation, differentiation,demise and apoptosis of blood cells are kept in equilibrium, which is well known to be mediated by a precise regulatory network of cytokines with stimulating factors and inhibiting factors. Acute leukemia is the most common clonal malignancy that are characterized by uncontrolled proliferation, blocked differentiation and inhibted apoptosis. Leukemic cells have been found to autocrine some cytokines which act in turn on their produced cells via receptors. We have studied expression of positive and negtive factors and their receptors in leukemia cell line and draw a conclusion that multi-autocrine loops exist in leukemia which may be related to leukemia.The subjects of the thesis were focused on the following aspects:1.The TGF-β1 level in the supernatant of acute leukemia cells, leukemia cell line and MNC from normal marrow were measured by ELISA. Long race RT-PCR was used to detect gene mutation of TGF-β1 and TGF-β type Ⅱ receptor.2. We transferred the plasmid including the whole TGF-β1cDNA to high tumorigenic HL-60 cell (hHL-60) by using Lipofectamin 2000-mediated transfection reagent. Proliferative potential was measured by colony formation assays, flow cytometry technology and detection of DNA fragmentation were applied to demonstrate the apoptosis of cells and we studied expression of TGF-β1,bcl-2,hTERT of transfected cells by means of RT-PCR.Our major results were obtained as follows :(1) The supernatant TGFβ1 levels were significantly dereased in acute leukemia cells and leukemia cell line. (2) The promoter sequence and coding sequence of TGF-β1 have not found mutation, while in TGF-β type Ⅱ receptor there exist a same insertion of 75 bp at the same place.(3) Extragenous TGF-β1 gene inhibit hHL-60cell proliferation and down-regulating the expression of hTERT, bcl-2.From above results, we conclude that TGF-β1 secreted by the acute leukemia cell and leukemia cell line was significantly decreased, and there exist TGF-β type Ⅱ receptor mutation in some patients .We also conclude that Extragenous TGF-β1 gene inhibit hHL-60cell proliferation by means of down-regulating the expression of hTERT, bcl-2. As a weakened control , TGF-β1 may play an important role in the pathogenesis of AL.