Overexpression of the ATP-binding cassette half-transporter, ABCG2 (Mxr/BCrp/ABCP1), in flavopiridol-resistant human breast cancer cells.
Overexpression of the ATP-binding cassette half-transporter, ABCG2 (Mxr/BCrp/ABCP1), in flavopiridol-resistant human breast cancer cells.
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发表时间：
2001
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通讯作者：
R. Robey;Wilma Y. Medina-Pérez;K. Nishiyama;T. Lahusen;K. Miyake;T. Litman;A. Senderowicz;Douglas D. Ross;S. Bates
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作者：
R. Robey;Wilma Y. Medina-Pérez;K. Nishiyama;T. Lahusen;K. Miyake;T. Litman;A. Senderowicz;Douglas D. Ross;S. Bates
我们试图描述黄烷醇与三磷酸腺苷结合盒(ABC)转运体家族成员之间的相互作用。高表达多药耐药-1(MDR-1)和多药耐药相关蛋白(MRP)的细胞对黄哌醇没有明显的耐药性，而高表达ABC半转运蛋白ABCG2(MXR/BCRP/ABCP1)的细胞株对黄哌醇耐药。10微米的黄吡哆醇能阻止MRP介导的钙调素外流，而100微米的黄吡哆醇则不影响PGP介导的罗丹明123的转运。为了确定黄烷醇耐药的可能机制，我们将人乳腺癌细胞株MCF-7暴露于浓度递增的黄烷醇中。由此产生的耐药亚系MCF-7 FLV1000保持在1,000 NM的黄烷醇中，并被发现对黄烷醇具有24倍的耐药性，对米托蒽醌(675倍)、拓扑替康(423倍)和伊立替康的活性代谢物SN-38(950倍)也具有高度的交叉耐药性。由于这种交叉耐药模式与ABCG2高表达细胞的报道一致，因此在5微米ABCG2抑制剂fumitremorgin C(FTC)存在下重复细胞毒性研究，MCF-7 FLV1000细胞对黄烷醇、米托蒽醌、SN-38和拓扑替康的敏感性恢复。进行了米托蒽醌外排研究，发现了高水平的FTC可逆的米托蒽醌外排。Northern印迹和聚合酶链式反应分析显示ABCG2基因过表达。Western印迹证实ABCG2过表达；未检测到P-糖蛋白和MRP的过表达。这些结果表明，ABCG2在黄吡哆醇的抗性中起一定作用。
We sought to characterize the interactions of flavopiridol with members of the ATP-binding cassette (ABC) transporter family. Cells overexpressing multidrug resistance-1 (MDR-1) and multidrug resistance-associated protein (MRP) did not exhibit appreciable flavopiridol resistance, whereas cell lines overexpressing the ABC half-transporter, ABCG2 (MXR/BCRP/ABCP1), were found to be resistant to flavopiridol. Flavopiridol at a concentration of 10 microM was able to prevent MRP-mediated calcein efflux, whereas Pgp-mediated transport of rhodamine 123 was unaffected at flavopiridol concentrations of up to 100 microM. To determine putative mechanisms of resistance to flavopiridol, we exposed the human breast cancer cell line MCF-7 to incrementally increasing concentrations of flavopiridol. The resulting resistant subline, MCF-7 FLV1000, is maintained in 1,000 nM flavopiridol and was found to be 24-fold resistant to flavopiridol, as well as highly cross-resistant to mitoxantrone (675-fold), topotecan (423-fold), and SN-38 (950-fold), the active metabolite of irinotecan. Because this cross-resistance pattern is consistent with that reported for ABCG2-overexpressing cells, cytotoxicity studies were repeated in the presence of 5 microM of the ABCG2 inhibitor fumitremorgin C (FTC), and sensitivity of MCF-7 FLV1000 cells to flavopiridol, mitoxantrone, SN-38, and topotecan was restored. Mitoxantrone efflux studies were performed, and high levels of FTC-reversible mitoxantrone efflux were found. Northern blot and PCR analysis revealed overexpression of the ABCG2 gene. Western blot confirmed overexpression of ABCG2; neither P-glycoprotein nor MRP overexpression was detected. These results suggest that ABCG2 plays a role in resistance to flavopiridol.