外源性TGF-β_1对NB4细胞内源性TGF-β_1的影响及其促凋亡机制的研究  

Proapoptotic mechanism and changes of endogenous TGF-β_1 in NB4 cells induced by exogenous TGF-β_1

作　　者：梁颖[1] 李艳[1] 卢香兰[1] 王艳萍[1] 高峰[1] 于锦香[1] 

机构地区：[1]中国医科大学第一附属医院血液科,辽宁沈阳110001

出　　处：《中国病理生理杂志》2010年第1期107-111,共5页Chinese Journal of Pathophysiology

基　　金：辽宁省科技攻关课题资助项目(No.2004225004-10)

摘　　要：目的:研究转化生长因子β1(TGF-β1)作用于NB4细胞后的细胞凋亡情况、细胞周期改变及内源性TGF-β1、P27Kip1、cyclin E及bcl-2 mRNA水平的变化。方法:瑞氏-吉姆萨染色观察凋亡细胞形态学的变化;流式细胞术检测细胞周期和凋亡;半定量RT-PCR技术检测内源性TGF-β1、P27Kip1、cyclin E以及bcl-2的mRNA水平。结果:TGF-β1能抑制NB4细胞的生长,促进NB4细胞的凋亡。5μg/LTGF-β1使NB4细胞阻滞在G1期。外源性TGF-β1浓度<5μg/L时,内源性TGF-β1的mRNA表达上调,外源性TGF-β1浓度为10μg/L时,内源性TGF-β1mRNA表达下调。5μg/LTGF-β1可使P27Kip1表达上调、cyclin E、bcl-2表达下调。结论:TGF-β1可诱导NB4细胞凋亡,引起细胞周期分布异常;外源性TGF-β1可能通过(1)上调内源性TGF-β1,从而使下游因子P27Kip1高表达以诱导NB4细胞凋亡;(2)TGF-β1直接抑制了cyclin E的表达,或者通过调高P27Kip1的表达反馈抑制cyclin E的活性,进而导致细胞周期阻滞;(3)通过下调bcl-2而诱导NB4细胞凋亡。高浓度的外源性TGF-β1可拮抗内源性TGF-β1表达,可能与其导致TGF-β1受体突变,或存在TGF-β1受体靶点过饱和现象有关。AIM ： To study the effects of transforming growth factor -β1 （ TGF -β1 ） on cell apoptosis, cell cycle, production of endogenous TGF -β1, expressions of P27Kip1 , cyclin E and bcl - 2 mRNA levels in NB4 cells. METHODS ： Apoptotic morphological changes were observed by Wright - Giemsa staining. Cell cycle and apoptosis were detected with flow cytometry. Semiquantitative RT - PCR was used to examine the mRNA levels of endogenous TGF -β1, P27Kip1 , cyclin E and bcl -2. RESULTS： TGF-β1 significantly restrained the growth and promoted the apoptosis of NB4 cells. The blockage of NB4 cells treated by TGF -β1 at concentration of 5 μg/L was in Gl phase. Endogenous TGF -β1 mRNA expression in NB4 cells was up - regulated when the concentration of exogenous TGF -β1 was 〈 5μg/L. Meanwhile, the expression of endogenous TGF -β1 mRNA was down - regulated when the concentration of exogenous TGF -β1 was 10 μg/ L. After treated with TGF -β1 at concentration of 5μg/L, P27Kip1 mRNA expression in NB4 cells was up -regulated, cyclin E and bcl-2 were reduced. CONCLUSION： TGF-β1 is able to induce apoptosis and cell cycle distribution abnormally in NB4 cells by （ 1 ） Up - regulation of endogenous TGF -β1, so that NB4 cells was induced into apoptosis through consequently high expression of P27Kip1. （2） TGF -β1 may lead to cell cycle arrest by inhibiting the expression of cyclin E directly, or by inhibiting the activity of cyclin E through the increased expression of P27Kip1. （3） Down - regulation of bcl -2 induces apoptosis of NB4 cells.

关 键 词：转化生长因子Β 细胞凋亡 P27KIP1 细胞周期蛋白E Bcl-2 

分 类 号：R363[医药卫生—病理学]