Doxorubicin activates FOXO3a to induce the expression of multidrug resistance gene ABCB1 (MDR1) in K562 leukemic cells
Doxorubicin activates FOXO3a to induce the expression of multidrug resistance gene ABCB1 (MDR1) in K562 leukemic cells
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DOI：
10.1158/1535-7163.mct-07-0397
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发表时间：
2008-03-01
影响因子：
5.7
通讯作者：
Lam, Eric W-F.
中科院分区：
文献类型：
--
作者：
Hui, Rosaline C-Y.;Francis, Richard E.;Lam, Eric W-F.
使用阿霉素敏感的K562细胞系和耐药衍生物系KD 3 O和KD 225作为模型，我们发现，获得多药耐药（MDR）与增强FOXO 3a活性和ABCB 1（MDR 1），质膜P-糖蛋白，作为各种抗癌药物的外排泵的表达。此外，诱导ABCB 1 mRNA表达的阿霉素治疗幼稚K562细胞也伴随着增加FOXO 3a活性。对转染的K562、KD 30和KD 225细胞（其中FOXO 3a活性可由4-hydroxytarnoxifen诱导）的分析表明，FOXO 3a在蛋白质、mRNA和基因启动子水平上调ABCB 1表达。相反，在KD 225细胞中内源性FOXO 3a表达的沉默抑制了该转运蛋白的表达。启动子分析和染色质免疫沉淀试验表明，FOXO 3a调节ABCB 1的表达涉及结合这个转录因子的近端启动子区域。此外，FOXO 3a的激活增加了KD 30细胞中ABCB 1药物外排的潜力，而siRNA沉默FOXO 3a显著降低了ABCB 1药物外排能力。总之，这些发现表明了一种新的机制，可以促进MDR，涉及FOXO 3a作为抗癌药物诱导的细胞毒性应激的传感器。虽然FOXO 3a最初可能触发细胞周期停滞和细胞死亡的程序，以响应阿霉素，持续的FOXO 3a激活促进耐药性和细胞的存活，通过激活ABCB 1的表达。
Using the doxorubicin-sensitive K562 cell line and the resistant derivative lines KD3O and KD225 as models, we found that acquisition of multidrug resistance (MDR) is associated with enhanced FOXO3a activity and expression of ABCB1 (MDR1), a plasma membrane P-glycoprotein that functions as an efflux pump for various anticancer agents. Furthermore, induction of ABCB1 rnRNA expression on doxorubicin treatment of naive K562 cells was also accompanied by increased FOXO3a activity. Analysis of transfected K562, KD30, and KD225 cells in which FOXO3a activity can be induced by 4-hydroxytarnoxifen showed that FOXO3a up-regulates ABCB1 expression at protein, mRNA, and gene promoter levels. Conversely, silencing of endogenous FOXO3a expression in KD225 cells inhibited the expression of this transport protein. Promoter analysis and chromatin immuno-precipitation assays showed that FOXO3a regulation of ABCB1 expression involves binding of this transcription factor to the proximal promoter region. Moreover, activation of FOXO3a increased ABCB1 drug efflux potential in KD30 cells, whereas silencing of FOXO3a by siRNA significantly reduced ABCB1 drug efflux ability. Together, these findings suggest a novel mechanism that can contribute towards MDR, involving FOXO3a as sensor for the cytotoxic stress induced by anticancer drugs. Although FOXO3a may initially trigger a program of cell cycle arrest and cell death in response to doxorubicin, sustained FOXO3a activation promotes drug resistance and survival of cells by activating ABCB1 expression.