周期蛋白A在白血病细胞中表达意义的临床与实验研究(英文)

Clinical and Laboratory Studies of Expression of Cyclin A in Leukemia Cells

不断增殖是肿瘤的基本特征。一些基本的细胞周期调控分子参与了肿瘤的形成。细胞周期蛋白A(cyclinA)是在G1/S期表达的细胞周期蛋白 (cyclin) ,其异常高表达参与了肿瘤的形成。为了探讨cyclinA异常高表达与白血病细胞恶性增殖的关系 ,采用流式细胞仪胞浆内间接免疫荧光 /DNA双染色法半定量分析了急性白血病患者、门诊接受骨髓穿刺的患者、健康献血者这三种不同来源的外周血或骨髓标本细胞 ,以及白血病细胞系 (HL 6 0 )cyclinA表达水平。为了进一步研究cyclinA在白血病细胞增殖中的作用 ,用在体内、体外均有抗肿瘤作用的六亚甲基二乙酰胺 (HMBA)在体外抑制白血病细胞系HL 6 0增殖 ,并诱导其分化。增殖抑制效应采用四唑盐还原试验和细胞周期分析来检测。细胞表面分化抗原CD33、CD11b改变来检测分化。结果发现 ,两组来自白血病标本的细胞S期cyclinA (即急性白血病患者外周血或骨髓幼稚细胞和白血病细胞系 )表达阳性率要远远高于另两组 (门诊骨髓穿刺的患者骨髓细胞和健康献血员外周血细胞 ) ;在HMBA抗肿瘤细胞系HL 6 0增殖实验中发现随药物剂量的加大 ,增殖抑制和分化程度呈剂量依赖性 ;同时 ,胞内cyclinA蛋白表达水平被明显下调了 ,也呈剂量依赖性。结论 :白血病细胞S期cyclinA异常高表达 。

Uncontrolled cell proliferation is the basic feature of cancer. Some of the prime cell cycle regulators are involved directly in tumorigenesis. Cyclin A, one of the G 1/S cyclin, can cause transformation. The purpose of this research was to investigate whether cyclin A overexpression was involved in leukemogenesis and proliferation of leukemia cells. The expression of cyclin A at S phase in leukemia cell line HL 60, blast cells of acute leukemia patients, bone marrow cells of outpatients without malignant hematological disease and peripheral blood cells of healthy donors was investigated by simultaneous indirect immunofluorence staining of intracellular antigen and DNA. To further investigate whether cyclin A played as a key molecular in cell proliferation, HL 60 cells were exposed to different concentrations of hexamethylene bisacetamide (HMBA). MTT dye absorbance of living cells and cell cycle analysis were adopted to evaluate growth arrest. Differentiation was evaluated by detection of the change of expression of CD11b and CD33 on cell surface. The results showed that overexpression of cyclin A was only found among specimens from acute leukemia and leukemia cell line. There was no elevated cyclin A detection for cyclin A among specimens from outpatients and healthy donors. In HMBA interference experiment, HMBA was able to induce growth arrest and monocytic macrophase differentiation of HL 60 cells in a dose dependent manner, and all these changes were associated with a marked down regluation of cyclin A expression. In condlusion, aberrant overexpression of cyclin A at S phase was only found in leukemia cell lines and blast cells from acute leukemia. The dose dependent effect of HMBA on cell growth and differentiation of HL 60 cell line which was consistent with the decrease of cyclin A expression in these cells suggested that the molecular mechanisms of HMBA inducement involved downregulation of cyclin A expression.