VINCA ALKALOIDS AND CELL PROLIFERATION

长春碱（VLB）和长春新碱（VCR）是重要的抗肿瘤药物。 尽管这些生物碱与纺锤体蛋白（微管蛋白）结合， 导致有丝分裂停滞，已被认为是他们的基础， 尽管它们具有抗有丝分裂作用，但其细胞毒性作用的机制尚不清楚。 我们已经证明，在低VLB培养的药物敏感性淋巴母细胞中， 浓度时，发生广泛的细胞溶解，表明细胞表面 相关药物作用。 细胞表面微管蛋白的存在 可能是他们对药物敏感的原因 同样地，在细胞中， 在体外VLB，新的糖蛋白出现在细胞表面。 直接 这些细胞表面蛋白与药物转运机制的关系 并且肿瘤细胞群体中的抗性尚未阐明。 也不是 关于这些标志物与 VLB/VCR的细胞周期时相相关细胞毒性。 我们现建议 提取、纯化和浓缩微管蛋白和表面标记蛋白（100 和160 K M. W）。 单克隆 这些标记的抗体将被标记并用于关联 在标记物，药物转运和来自一个细胞的单个细胞的耐药性之间， 人口 我们将分析的外观和内容之间的关系 单个细胞上的标志物和细胞周期相关的 VLB/VCR的细胞毒性。 离心淘洗，密度梯度 分离和荧光激活细胞分选将用于 定量结合抗体的量，并收集选择性富集的 人口数量。 放射性标记药物将用于研究药物转运。 多参数流动分析将用于关联细胞周期阶段和 细胞表面标记。 与对细胞增殖影响的相关性 将在软琼脂试验和裸鼠异种移植中进行研究。

Vinblastine (VLB) and VIncristine (VCR) are important antitumor agents. Although binding of these alkaloids to spindle proteins (tubulin), resulting in mitotic arrest, has been suggested as the basis for their antimitotic action, the mechanism for their cytotoxic action is not known. We have shown that in drug sensitive lymphoblasts incubated with low VLB concentrations, extensive cytolysis occurs suggesting a cell surface related drug effect. The presence of cel surface tubulin in these cells may account for their drug sensitivity. Similarly, in cells made resistant in vitro to VLB, new glycoproteins appear on the cell surface. The direct relation of these cell surface proteins to the mechanism of drug transport and resistance in a tumor cel population has not been elucidated. Nor is any information available on the relation between these markers and the cell cycle phase related cytotoxicity of VLB/VCR. We now propose to extract, purify and concentrate tubulin and surface marker proteins (100 and 160 K M.W) from drug sensitive and resistant cells. Monoclonal antibodies to these markers will be labeled and used for correlation between markers, drug transport and resistance in individual cells from a population. We will analyze relation between the appearance and content of the markers on individual cells and the cell cycle phase related cytotoxicity of VLB/VCR. Centrifugal elutriation, density gradient separation and fluorescence activated cell sorting will be used to quantitate amount of bound antibodies and to collect selectively enriched populations. Radiolabelled drugs will be used to study drug transport. Multiparameter flow analysis will be used to correlate cell cycle stage and cell surface labelling. Correlation with effects on cell proliferation will be studied in soft agar assays and nude mice xenografts.