Cannell G R, Vesey D A, Dickinson R G
Centre for Studies in Drug Disposition, Department of Medicine, The University of Queensland at Royal Brisbane Hospital, Australia.
Life Sci. 2001 Nov 21;70(1):37-48. doi: 10.1016/s0024-3205(01)01370-4.
Many nonsteroidal anti-inflammatory drugs (NSAIDs) which have antiproliferative activity in colon cancer cells are carboxylate compounds forming acyl glucuronide metabolites. Acyl glucuronides are potentially reactive, able to hydrolyse, rearrange into isomers, and covalently modify proteins under physiological conditions. This study investigated whether the acyl glucuronides (and isomers) of the carboxylate NSAIDs diflunisal, zomepirac and diclofenac had antiproliferative activity on human adenocarcinoma HT-29 cells in culture. Included as controls were the carboxylate NSAIDs themselves, the non-carboxylate NSAID piroxicam, and the carboxylate non-NSAID valproate, as well as its acyl glucuronide and isomers. The compounds were incubated at 1-3000 microM with HT-29 cells for 24 hr, with [3H]-thymidine added for an additional 2 hr incubation. IC50 values were calculated from the concentration-inhibition response curves for thymidine uptake. The four NSAIDs inhibited thymidine uptake, with IC50 values about 200-500 microM. All of the NSAID acyl glucuronides (and isomers, tested in the case of diflunisal) showed antiproliferative activity broadly comparable to the parent drugs. This activity may stem from direct uptake of intact glucuronide/isomers followed by covalent modification of proteins critical in the cell replication process. However, hydrolysis during incubation and cellular uptake of liberated parent NSAID will play a role. In HT-29 cells incubated with zomepirac, covalently modified proteins in cytosol were detected by immunoblotting with a zomepirac antibody, suggesting that HT-29 cells do have the capacity to glucuronidate zomepirac. The anti-epileptic drug valproate had no effect on inhibition of thymidine uptake, though, surprisingly, its acyl glucuronide and isomers were active. The reasons for this are unclear at present.
许多在结肠癌细胞中具有抗增殖活性的非甾体抗炎药（NSAIDs）是形成酰基葡萄糖醛酸代谢物的羧酸盐化合物。酰基葡萄糖醛酸具有潜在的反应活性，能够在生理条件下水解、重排成异构体并与蛋白质发生共价修饰。本研究调查了羧酸盐类NSAIDs双氯芬酸、佐美酸和双氯芬酸的酰基葡萄糖醛酸（及其异构体）对培养的人腺癌HT - 29细胞是否具有抗增殖活性。作为对照的包括羧酸盐类NSAIDs本身、非羧酸盐类NSAID吡罗昔康、羧酸盐类非NSAID丙戊酸盐及其酰基葡萄糖醛酸和异构体。将这些化合物与HT - 29细胞在1 - 3000微摩尔浓度下孵育24小时，再加入[³H] - 胸苷继续孵育2小时。根据胸苷摄取的浓度 - 抑制反应曲线计算IC50值。这四种NSAIDs抑制胸苷摄取，IC50值约为200 - 500微摩尔。所有NSAID酰基葡萄糖醛酸（以及双氯芬酸测试的异构体）显示出与母体药物大致相当的抗增殖活性。这种活性可能源于完整葡萄糖醛酸/异构体的直接摄取，随后对细胞复制过程中关键的蛋白质进行共价修饰。然而，孵育过程中的水解以及释放的母体NSAID的细胞摄取也会起作用。在用佐美酸孵育的HT - 29细胞中，通过用佐美酸抗体进行免疫印迹检测到胞质溶胶中有共价修饰的蛋白质，这表明HT - 29细胞确实具有将佐美酸葡萄糖醛酸化的能力。抗癫痫药物丙戊酸盐对胸苷摄取的抑制没有影响，不过令人惊讶的是，其酰基葡萄糖醛酸和异构体具有活性。目前其原因尚不清楚。
