Antitumor Agents. 185. Synthesis and Biological Evaluation of Tridemethylthiocolchicine Analogues as Novel Topoisomerase II Inhibitors
摘要:
Several 1,2,3-tridemethyldeacetylthiocolchicine derivatives have been synthesized and evaluated for cytotoxic activity against various human tumor cell lines and for their inhibitory effects on DNA topoisomerases in vitro. Exhaustive demethylation of thiocolchicine analogues completely changes their biological profiles. Instead of displaying antitubulin activity, most target compounds inhibited topoisomerase II activity. Only compounds with a larger side chain, such as 15a, 23a, and 24a, did not interfere with topoisomerase II enzymatic functions. The cytotoxicity of target compounds was reduced by 3 orders of magnitude compared to that of colchicine in most cell lines, The hydrophilicity of phenolic compounds might prevent drug passage through the cell plasma membrane and, thus, be responsible for the relatively weak cytotoxicity. To test this hypothesis, 27-30 were prepared from 16a by protecting all hydroxy groups with esters with an aim to facilitate drug transportation. In vitro cytotoxicity assays indicated that 27 was more potent than its parent compound in all tested tumor cell lines and showed tissue selective cytotoxicity with a significant inhibitory effect against KB cells (IC50 = 2.7 mu g/mL). Therefore, we propose that 27 acts as a prodrug, liberating 16a to exert its antitopoisomerase activity and, finally, to cause cell death.
合成了三个新的硫代秋水仙碱类似物系列,N-酰基-,N-芳酰基-和N-(取代的苄基)-去乙酰基硫代秋水仙碱类,并评估了它们对各种肿瘤细胞系,特别是实体肿瘤细胞系的细胞毒性,以及它们的毒性。体外对微管蛋白聚合的抑制作用。这些化合物中的大多数对微管蛋白的聚合均显示出强大的抑制作用,可与硫代秋水仙碱相比,但大于秋水仙碱。只有在C(7)位置具有长侧链的化合物,例如22-24,才不会抑制微管蛋白聚合。与大多数类秋水仙碱类药物观察到的负旋光度相反,几种活性N-芳酰基脱乙酰基硫代秋水仙碱类似物具有正旋光度。该性质可能归因于联芳构型从正常的aS逆转为aR。因此,通过圆二色性进一步评估了N-芳酰基类似物,该二色性容易区分aS和aR联芳基构型。后一种技术证明了活性N-芳酰基类似物确实具有aS构型,尽管它们具有正旋光度。然而,N-(取代的苄基)-脱乙酰基硫代秋水仙碱与相应的N-芳酰基-脱乙酰基硫代秋水仙碱的1 H
A simple chemoenzymatic strategy for the incorporation of bioactive and suitably functionalized molecules into a polyesterchain has been developed. The protocol involves first the reaction of a primaryamine with ε-caprolactone to give an amide carrying a terminal primary hydroxy group, followed by the enzymatic growth of the polymeric chain triggered by Novozym 435. This method is versatile and easy