Transport of 7-ethyl-10-hydroxycamptothecin (SN-38) by breast cancer resistance protein ABCG2 in human lung cancer cells
Transport of 7-ethyl-10-hydroxycamptothecin (SN-38) by breast cancer resistance protein ABCG2 in human lung cancer cells
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DOI：
10.1006/bbrc.2001.5850
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发表时间：
2001-11-09
影响因子：
3.1
通讯作者：
Kohno, S
中科院分区：
文献类型：
--
作者：
Nakatomi, K;Yoshikawa, M;Kohno, S
据报道，乳腺癌耐药蛋白 (BCRP) ABCG2 的过度表达使癌细胞对基于喜树碱的抗癌药物产生耐药性，例如拓扑替康和 7-乙基-10-羟基喜树碱（SN-38：伊立替康的活性代谢物）。我们最近表明，SN-38选择的PC-6/SN2-5H人肺癌细胞过表达BCRP，并且细胞内SN-38和SN-38-葡萄糖醛酸积累减少(S.Kawabata等人，Biochem Biophys.Res.Commun.280, 1216-1223, 2001)。在本研究中，我们通过使用来自亲本 PC-6 和耐药 PC-6/SN2-5H 细胞的质膜囊泡，检查了 BCRP 是否在体外转运 SN-38 和/或 SN-38-葡萄糖醛酸苷，其中通过 HPLC 测量了膜囊泡中 SN-38 和 SN-38-葡萄糖醛酸苷的积累。 SN-38 和 SN-38-葡萄糖醛酸苷均依赖于 ATP 转运至 PC-6/SN2-5H 细胞制备的膜囊泡中，而在 PC-6 细胞的膜囊泡中未观察到转运活性。在 PC-6/SN2-5H 囊泡中观察到的运输动力学参数为：对于 SN-38，K-m = 4.0 muM，V-max = 714 pmol/mg/min；对于 SN-38-葡萄糖醛酸苷，K-m = 26 muM，V-max = 833 pmol/mg/min。这些发现表明，PC-6/SN2-5H 细胞中表达的 BCRP 可以转运 SN-38 和 SN-38-葡萄糖醛酸苷，对 SN-38 具有更高的亲和力。 (C) 2001 年学术出版社。
Overexpression of breast cancer resistance protein (BCRP) ABCG2 reportedly confers cancer cell resistance to camptothecin-based anticancer drugs, such as topotecan and 7-ethyl-10-hydroxycamptothecin (SN-38: the active metabolite of irinotecan). We have recently shown that SN-38-selected PC-6/SN2-5H human lung carcinoma cells overexpressed BCRP with the reduced intracellular accumulation of SN-38 and SN-38-glucuronide (S. Kawabata et al, Biochem Biophys. Res. Commun. 280, 1216-1223, 2001). In the present study, we have examined whether BCRP transports SN-38 and/or SN-38-glucuronide in vitro, by using plasma membrane vesicles from the parental PC-6 and resistant PC-6/SN2-5H cells, where SN-38 and SN-38-glucuronide accumulation in membrane vesicles was measured by HPLC. Both SN-38 and SN-38-glucuronide were ATP-dependently transported into membrane vesicles prepared from PC-6/SN2-5H cells, whereas no transport activity was observed in membrane vesicles from PC-6 cells. The kinetic parameters of the transport observed in PC-6/SN2-5H vesicles were K-m = 4.0 muM, V-max = 714 pmol/mg/min for SN-38 and K-m = 26 muM, V-max = 833 pmol/mg/min for SN-38-glucuronide. These findings suggest that BCRP expressed in PC-6/SN2-5H cells transports both SN-38 and SN-38-glucuronide with a higher affinity toward SN-38. (C) 2001 Academic Press.