It is presently accepted that the mechanism of action for all anti-tumor tubulin ligands involves the perturbation of microtubule dynamics during the G2/M phase of cell division and subsequent entry into apoptosis (1). In this invention, we report a novel tubulin ligands which have a unique mechanism of action. These compounds,. halogenated derivatives of acetamido benzoyl ethyl ester (HAABE), arrest cancer cells in S-phase and cause cell death by a combination of apoptosis (DNA ladder) and necrosis (DNA degradation) type mechanisms. Normal cells are not affected at the same concentrations of compound. The ligands bind covalently to tubulin in vitro and in vivo and shows potent cancericidal activity in tissue culture assays and in animal tumor models. These compounds target early S-phase at the G1/S transition rather than the G2/M phase and mitotic arrest. Bcl-2 phosphorylation, a marker of mitotic microtubule inhibition by other tubulin ligands was dramatically altered, phosphorylation was rapid and biphasic rather than a slow linear event. The halogenated ethyl ester series of derivatives thus constitute a unique set of tubulin ligands which induce a novel mechanism of cancer cell death.
目前公认,所有抗肿瘤微管蛋白
配体的作用机制都是在细胞分裂的 G2/M 阶段扰乱微管动力学,随后进入细胞凋亡阶段(1)。在本发明中,我们报告了一种具有独特作用机制的新型微管蛋白
配体。这些化合物,即乙酰
氨基苯甲酰
乙酯的卤代衍
生物(H
AABE),可使癌细胞停滞在 S 期,并通过凋亡(DNA 梯形)和坏死(DNA 降解)两种机制导致
细胞死亡。相同浓度的化合物不会影响正常细胞。
配体在体外和体内与微管蛋白共价结合,在组织培养试验和动物肿瘤模型中显示出强大的杀癌活性。这些化合物针对的是 G1/S 转换的早期 S 期,而不是 G2/M 期和有丝分裂停滞期。Bcl-2
磷酸化是其他微管蛋白
配体抑制有丝分裂微管的标志,这些化合物的
磷酸化发生了显著变化,
磷酸化迅速且呈双相,而不是缓慢的线性
磷酸化。因此,卤代
乙酯系列衍
生物构成了一组独特的微管蛋白
配体,可诱导一种新的癌
细胞死亡机制。