Halichondrin B and homohalichondrin B, marine natural products binding in the vinca domain of tubulin. Discovery of tubulin-based mechanism of action by analysis of differential cytotoxicity data.
Halichondrin B and homohalichondrin B, marine natural products binding in the vinca domain of tubulin. Discovery of tubulin-based mechanism of action by analysis of differential cytotoxicity data.
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DOI：
10.1016/s0021-9258(18)98491-7
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发表时间：
1991-08
期刊：
影响因子：
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通讯作者：
R. Bai;K. Paull;C. L. Herald;L. Malspeis;G. Pettit;E. Hamel
中科院分区：
文献类型：
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作者：
R. Bai;K. Paull;C. L. Herald;L. Malspeis;G. Pettit;E. Hamel
在新的国家癌症研究所药物评价计划中产生的数据，该计划基于对60种人类肿瘤细胞系中细胞生长的抑制，用于比较新化合物与已知作用机制的药物的差异细胞毒性。两个海洋天然产物，软海绵素B和homohalichondrin B，反复出现时，数据库与已知的抗有丝分裂剂探测。我们证实，这两种化合物都具有高度细胞毒性（对L1210小鼠白血病细胞的IC50值分别为0.3和1 nM），在毒性浓度下，细胞在有丝分裂中蓄积，这两种化合物都抑制了纯化的微管蛋白的聚合，并且都抑制了依赖于微管相关蛋白的微管组装。活性较低的高软海绵素B的量有限，因此仅对软海绵素B进行了详细研究。软海绵素B不干扰秋水仙碱与微管蛋白的结合，但它是长春碱与微管蛋白结合的非竞争性抑制剂（表观Ki，5.0 μ M）。因此，将软海绵素B与干扰长春花生物碱与微管蛋白结合的其它试剂（长春碱、美登素、海兔毒素10、根视素A、根霉素）在其对微管蛋白聚合、抑制GTP水解、抑制核苷酸交换和稳定微管蛋白的作用以及其对长春花生物碱结合和抑制细胞生长的作用的定量评估方面进行比较。由于软海绵素B最初与磷酸酶抑制剂冈田酸分离自相同的生物体，并且由于其作为L1210细胞生长抑制剂的有效性是冈田酸的约50倍，因此应谨慎解释用冈田酸处理后观察到的细胞微管扰动。
Data generated in the new National Cancer Institute drug evaluation program, which is based on inhibition of cell growth in 60 human tumor cell lines, were used to compare new compounds with agents of known mechanism of action in terms of their differential cytotoxicity. Two marine natural products, halichondrin B and homohalichondrin B, appeared repeatedly when the data base was probed with known antimitotic agents. We confirmed that both compounds were highly cytotoxic (IC50 values for L1210 murine leukemia cells of 0.3 and 1 nM, respectively), with accumulation of cells arrested in mitosis at toxic concentrations, that both inhibited the polymerization of purified tubulin, and that both inhibited microtubule assembly dependent on microtubule-associated proteins. Limited amounts of homohalichondrin B, the less active agent, were available, so only halichondrin B was studied in detail. Halichondrin B did not interfere with colchicine binding to tubulin, but it was a noncompetitive inhibitor of the binding of vinblastine to tubulin (apparent Ki, 5.0 microM). Halichondrin B was therefore compared with other agents which interfere with the binding of vinca alkaloids to tubulin (vinblastine, maytansine, dolastatin 10, phomopsin A, rhizoxin) in terms of its effects on tubulin polymerization, inhibition of GTP hydrolysis, inhibition of nucleotide exchange, and stabilization of tubulin, as well as the quantitative assessment of its effects on vinca alkaloid binding and inhibition of cell growth. Since halichondrin B was originally isolated from the same organism as the phosphatase inhibitor okadaic acid, and since it is about 50-fold more effective than okadaic acid as an inhibitor of L1210 cell growth, perturbations of cellular microtubules observed following treatment with okadaic acid should be interpreted cautiously.