Low-level doxorubicin resistance in benzo[a]pyrene-treated KB-3-1 cells is associated with increased LRP expression and altered subcellular drug distribution
Low-level doxorubicin resistance in benzo[a]pyrene-treated KB-3-1 cells is associated with increased LRP expression and altered subcellular drug distribution
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DOI：
10.1006/taap.2000.8903
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发表时间：
2000-04-15
影响因子：
3.8
通讯作者：
Fong, WF
中科院分区：
文献类型：
--
作者：
Cheng, SH;Lam, W;Fong, WF
P -糖蛋白（P - gp）阴性的表皮样咽癌细胞KB - 3 - 1在0.25 mM苯并[a]芘（BaP）中培养3个月后，对阿霉素产生了耐药性，但对长春碱、秋水仙碱或顺铂没有耐药性。环孢菌素（P - gp抑制剂）未改变对阿霉素的耐药性。P - gp和多药耐药蛋白（MRP）的底物BaP或钙黄绿素在细胞内的积累不受P - gp和MRP抑制剂的影响。对细胞色素P450（CYP）1A1、肺耐药相关蛋白（LRP）、P - gp和MRP的表达进行了研究。发现CYP1A和LRP在mRNA和蛋白质水平上过度表达。经BaP处理的KB - 3 - 1细胞仍为P - gp阴性，而MRP水平未改变。发现BaP在亚细胞中的积累定位于细胞质，在BaP处理细胞的细胞核中极少。相比之下，在未处理的细胞中发现BaP均匀地渗透到细胞核和细胞质中。BaP处理后阿霉素的亚细胞分布发生改变，该抗癌药物在细胞质细胞器中局部积累，但不在细胞核中。我们的数据表明LRP可能对有毒化合物起保护作用。LRP（而非P - gp或MRP）表达增加与核靶点中阿霉素积累减少相关，这表明这种核周转运蛋白在P - gp阴性癌细胞的多药耐药表型中起关键作用。这些结果还提出了一种癌症药物耐药性产生的替代机制，即环境毒物和致癌物BaP处理后诱导LRP活性。（C）2000学术出版社
The P-glycoprotein (P-gp)-negative epidermoid pharyngeal carcinoma cells KB-3-1 were grown in 0.25 mM benzo[a]pyrene (BaP) for 3 months and increased resistance to doxorubicin, but not to vinblastine, colchicine, or cisplatin, was found. Doxorubicin resistance was not altered by cyclosporin, the P-gp inhibitor, Intracellular accumulation of BaP or calcein, a substrate for P-gp and multidrug resistance protein (MRP), was not altered by inhibitors of the P-gp and MRP, The expression of cytochrome P450 (CYP) 1A1, lung-resistance-related protein (LRP), P-gp, and MRP was investigated, Overexpression of CYP1A and LRP, on the mRNA and protein levels, was found. BaP-treated KB-3-1 cells remained P-gp negative while the level of MRP was not altered. Subcellular accumulation of BaP was found to be localized in the cytoplasm and minimal in the nuclei in BaP treated cells. In contrast, even penetration of BaP to the nuclei and cytoplasm was found in untreated cells. Subcellular distribution of doxorubicin was altered following BaP treatment with localized accumulation of the cancer drug in cytoplasmic organelles but not in the nuclei. Our data suggested that LRP might play a protective role against toxic compounds. The correlation of increased expression of LRP, but not P-gp nor MRP, with decreased doxorubicin accumulation in the nuclear target suggests a pivotal role of this perinuclear transporter in the MDR phenotype of P-gp-negative cancer cells. These results also propose an alternative mechanism of cancer drug resistance emergence, namely, induction of LRP activity following treatment with BaP, an environmental toxicant and a carcinogen. (C) 2000 Academic Press.