Bai R, Pettit G R, Hamel E
Division of Cancer Treatment, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892.
Biochem Pharmacol. 1990 Jun 15;39(12):1941-9. doi: 10.1016/0006-2952(90)90613-p.
Dolastatin 10, a cytostatic peptide containing several unique amino acid subunits, was isolated from the marine shell-less mollusk Dolabella auricularia (Pettit GR, Kamano Y, Herald CL, Tuinman AA, Boettner FE, Kizu H, Schmidt JM, Baczynskyj L, Tomer KB and Bontems RJ, J Am Chem Soc 109: 6883-6885, 1987). Since our preliminary studies demonstrated that dolastatin 10 inhibited tubulin polymerization and the binding of radiolabeled vinblastine to tubulin, an initial characterization of the properties of dolastatin 10 included a comparison to other antimitotic drugs interfering with vinca alkaloid binding to tubulin (vinblastine, maytansine, rhizoxin, and phomopsin A). Dolastatin 10 inhibited the growth of L1210 murine leukemia cells in culture, with a concordant rise in the mitotic index, and its IC50 value for cell growth was 0.5 nM. Comparable values for the other drugs were 0.5 nM for maytansine, 1 nM for rhizoxin, 20 nM for vinblastine, and 7 microM for phomopsin A. IC50 values were also obtained for the polymerization of purified tubulin in glutamate: 1.2 microM for dolastatin 10, 1.4 microM for phomopsin A, 1.5 microM for vinblastine, 3.5 microM for maytansine, and 6.8 microM for rhizoxin. Dolastatin 10 and vinblastine were comparable in their effects on microtubule assembly dependent on microtubule-associated proteins. Preliminary studies indicated that dolastatin 10, like vinblastine, causes formation of a cold-stable tubulin aggregate at higher drug concentrations. We confirmed that rhizoxin, phomopsin A, and maytansine also inhibit the binding of radiolabeled vinblastine and vincristine to tubulin. Dolastatin 10 and phomopsin A were the strongest inhibitors of these reactions, and rhizoxin the weakest. Dolastatin 10, phomopsin A, maytansine, vinblastine, and rhizoxin all inhibited tubulin-dependent GTP hydrolysis. The greatest inhibition of hydrolysis was observed with dolastatin 10 and phomopsin A, and the least inhibition with rhizoxin.
多拉司他汀10是一种含有几个独特氨基酸亚基的细胞生长抑制剂肽，它是从海洋无壳软体动物耳状芋螺（Pettit GR、Kamano Y、Herald CL、Tuinman AA、Boettner FE、Kizu H、Schmidt JM、Baczynskyj L、Tomer KB和Bontems RJ，《美国化学会志》109：6883 - 6885，1987年）中分离得到的。由于我们的初步研究表明多拉司他汀10能抑制微管蛋白聚合以及放射性标记长春碱与微管蛋白的结合，对多拉司他汀10性质的初步表征包括与其他干扰长春花生物碱与微管蛋白结合的抗有丝分裂药物（长春碱、美登素、根霉素和腐草霉素A）进行比较。多拉司他汀10在培养中抑制L1210小鼠白血病细胞的生长，同时有丝分裂指数相应升高，其对细胞生长的IC50值为0.5 nM。其他药物的可比数值分别为：美登素0.5 nM、根霉素1 nM、长春碱20 nM、腐草霉素A 7 microM。还获得了纯化微管蛋白在谷氨酸中聚合的IC50值：多拉司他汀10为1.2 microM、腐草霉素A为1.4 microM、长春碱为1.5 microM、美登素为3.5 microM、根霉素为6.8 microM。多拉司他汀10和长春碱对依赖微管相关蛋白的微管组装的影响相当。初步研究表明，多拉司他汀10与长春碱一样，在较高药物浓度下会导致形成冷稳定的微管蛋白聚集体。我们证实根霉素、腐草霉素A和美登素也抑制放射性标记长春碱和长春新碱与微管蛋白的结合。多拉司他汀10和腐草霉素A是这些反应最强的抑制剂，根霉素是最弱的。多拉司他汀10、腐草霉素A、美登素、长春碱和根霉素均抑制依赖微管蛋白的GTP水解。观察到多拉司他汀10和腐草霉素A对水解的抑制作用最大，根霉素的抑制作用最小。
