Jordan M A, Thrower D, Wilson L
Department of Biological Sciences, University of California, Santa Barbara 93106.
Cancer Res. 1991 Apr 15;51(8):2212-22.
We have used a structure-activity approach to investigate whether the Vinca alkaloids inhibit cell proliferation primarily by means of their effects on mitotic spindle microtubules or by another mechanism or by a combination of mechanisms. Five Vinca alkaloids were used to investigate the relationship in HeLa cells between inhibition of cell proliferation and blockage of mitosis, alteration of spindle organization, and depolymerization of microtubules. Indirect immunofluorescence staining of microtubules and 4,6-diamidino-2-phenylindole staining of chromatin were used to characterize the effects of the drugs on the distributions of cells in stages of the cell cycle and on the organization of microtubules and chromosomes in metaphase spindles. The microtubule polymer was isolated from cells and quantified using a competitive enzyme-linked immunoadsorbent assay for tubulin. We observed a nearly perfect coincidence between the concentration of each Vinca derivative that inhibited cell proliferation and the concentration that caused 50% accumulation of cells at metaphase, despite the fact that the antiproliferative potencies of the drugs varied over a broad concentration range. Inhibition of cell proliferation and blockage of cells at metaphase at the lowest effective concentrations of all Vinca derivatives occurred with little or no microtubule depolymerization or spindle disorganization. With increasing drug concentrations, the organization of microtubules and chromosomes in arrested mitotic spindles deteriorated in a manner that was common to all five congeners. These results indicate that the antiproliferative activity of the Vinca alkaloids at their lowest effective concentrations in HeLa cells is due to inhibition of mitotic spindle function. The results suggest further that the Vinca alkaloids inhibit cell proliferation by altering the dynamics of tubulin addition and loss at the ends of mitotic spindle microtubules rather than by depolymerizing the microtubules. The specific alterations of spindle microtubule dynamics appear to differ among the five Vinca congeners, and such differences may be responsible for differences in the antitumor specificities of the drugs.
我们采用结构-活性方法来研究长春花生物碱是否主要通过其对有丝分裂纺锤体微管的作用、或通过另一种机制、或通过多种机制的组合来抑制细胞增殖。使用五种长春花生物碱来研究在HeLa细胞中细胞增殖抑制与有丝分裂阻滞、纺锤体组织改变以及微管解聚之间的关系。利用微管的间接免疫荧光染色和染色质的4,6-二脒基-2-苯基吲哚染色来表征药物对细胞周期各阶段细胞分布以及中期纺锤体中微管和染色体组织的影响。从细胞中分离微管聚合物，并使用针对微管蛋白的竞争性酶联免疫吸附测定法进行定量。我们观察到，尽管这些药物的抗增殖效力在很宽的浓度范围内有所不同，但每种长春花衍生物抑制细胞增殖的浓度与导致50%细胞在中期积累的浓度几乎完全吻合。在所有长春花衍生物的最低有效浓度下，细胞增殖的抑制和细胞在中期的阻滞发生时，微管解聚或纺锤体紊乱很少或没有。随着药物浓度的增加，停滞有丝分裂纺锤体中微管和染色体的组织以所有五种同系物共有的方式恶化。这些结果表明，长春花生物碱在HeLa细胞中最低有效浓度下的抗增殖活性是由于有丝分裂纺锤体功能的抑制。结果还进一步表明，长春花生物碱通过改变有丝分裂纺锤体微管末端微管蛋白添加和丢失的动力学来抑制细胞增殖，而不是通过使微管解聚。纺锤体微管动力学的具体改变在五种长春花同系物之间似乎有所不同，这种差异可能是药物抗肿瘤特异性差异的原因。
