维生素A类化合物和二甲基亚砜诱导人早幼粒白血病细胞(HL-60)分化的显微与亚显微结构研究

用光镜和电镜技术研究了HL-60细胞在诱导分化过程中的显微与亚显微结构变化,10~(-6)M的维A酸处理6天,细胞按粒系途径定向分化,其核质比例降低,核浓缩、分叶,核仁减少或消失。经RA处理的细胞在电镜下出现下列明显的变化:细胞核浓缩和分叶,异染色质区域增加,约46%细胞显示出类似成熟粒细胞核的亚显微形态特征,胞质中嗜天青颗粒减少,特异颗粒显著增加,两种颗粒的比率发生明显变化;细胞质中微管、微丝的量增加;多聚和单个分散的游离核糖体减少,有些??细胞胞质空泡化;出现主要以微丝为筑架的大型钝形伪足和不规则的表面突起。上述这些变化似可作为HL-60细胞形态分化的标志。维A酸诱导HL-60细胞形态分化具有明显的时间效应关系。1.4%DMSO对HL-60细胞分化的诱导作用类似于10~(-6)MRA,而等剂量的(10~(-6)M)R Ⅰ、RⅡ其作用弱于RA。

STUDIES ON MICROSCOPIC AND SUBMICROSCOPIC STRUCTURE OF HUMAN PROMYELOCYTIC LEUKEMIA CELLS(HL-60) DURING DIFFERENTIATION INDUCED BY RETINOIDS AND DIMETHYL SULFOXIDE

The changes of microscopic and submicroscopic structure were studied by light and electron microscopy in human promyelocytic leukemia cells (HL-60) treated with retinoids and dimethyl sulfoxide.After treatment with retinoic acid (RA) at 10~(-6) M for 6 days,HL-60 cells differentiated along myeloid pathway and had a decreased nucleocytoplasmic ratio accompanied with nuclear conden- sation and segmentation.Electron microscopy of RA-treated cells revealed five remarkable changes:(1) The nuclei displayed dramatic nuclear segmentation and increased definition of heterochromatic areas.About 46 percent of the RA-treated cells showed morphological characteristics similar to mature granulocytes.(2) The cyto- plasm of treated cells demonstrated evidence of decrease of azurophilic granules and increase of specific gra- nules.A predominant change has took place in the ratio between the two kind of granules.(3) A significant increase in the amount of microfila- ments and microtubules was observed in the cytoplasm of treated cells. (4) The single and polyribosomes of the cytoplasm decreased and cyto- plasm of the treated cells became more vacuolus.(5) There appeared large blunt pseudopodia and irregular sur- face extensions of the treated cells. These changes mentioned above could be considered as markers of mor- phological differentiation of HL-60 cells. The morphological differentia- tion induced by retinoic acid was time- dependent.Only after incubation with retinoic acid for 3 days,did the HL-60 cells show predominant micro- scopic and submicroscopic structural changes.On the induction of HL- 60 cells differentiation,1.4% dimethyl sulfoxide had similar action to RA. N-(4-ethoxycarbophenyl) retinamide (RI) and N-(4-hydroxycarbophenyl) retinamide (RII),the derivatives of retinoic acid,showed weaker ability than that of RA to induce terminal differentiation of HL-60 cells.