Folate deprivation induces BCRP (ABCG2) expression and mitoxantrone resistance in Caco-2 cells
Folate deprivation induces BCRP (ABCG2) expression and mitoxantrone resistance in Caco-2 cells
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DOI：
10.1002/ijc.23677
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发表时间：
2008-10-01
影响因子：
6.4
通讯作者：
Peters, Godefridus J.
中科院分区：
文献类型：
--
作者：
Lemos, Clara;Kathmann, Ietje;Peters, Godefridus J.
叶酸可以诱导乳腺癌耐药蛋白 (BCRP) 和多药耐药蛋白 1 (MRP1) 的表达和活性。我们的目的是研究叶酸剥夺/补充对 (i) BCRP 和 MRP 表达以及 (ii) 这些转运蛋白介导的耐药性的时间依赖性影响。因此，通常在含有超生理叶酸（FA）浓度（2.3μM；高叶酸，HF）的标准RPMI培养基中生长的Caco-2结肠癌细胞逐渐适应更高生理叶酸浓度（1nM亚叶酸（LV）或1nM FA；低叶酸，LF），产生亚系Caco-2-LF/LV和Caco-2-LF/FA。 Caco-2-LF/LV 和 LF/FA 细胞的 BCRP-mRNA 表达最大增加了 5.2 倍和 9.6 倍，BCRP 蛋白表达最大增加了 3.9 倍和 5.7 倍，但 MRP 表达没有重大变化。 LF 细胞中 BCRP 的过度表达导致对米托蒽醌 (MR) 的耐药性增加了 3.6 至 6.3 倍，而 BCRP 抑制剂 Ko143 可以完全逆转这种耐药性。另一方面，在暴露 4 小时（Caco-2-LF/LV 和 LF/FA 分别为 9,870 倍和 23,923 倍）和 72 小时（Caco-2-LF/LV 和 LF/FA 分别为 11 倍和 22 倍）后，LF 适应细胞对甲氨蝶呤的敏感性明显高于 HF 对应细胞。用共聚焦激光扫描显微镜观察的免疫荧光染色显示，在Caco-2细胞（HF和LF）中，BCRP主要位于细胞质中。总之，叶酸剥夺会诱导 Caco-2 细胞中与 MR 耐药相关的 BCRP 表达。 BCRP 在这些细胞中的细胞内定位表明，这种转运蛋白主要不是将其底物挤出细胞，而是进入细胞内隔室，叶酸可以在其中储存。 (C) 2008 年威利利斯。公司
Folates can induce the expression and activity of the breast-cancer- resistance-protein (BCRP) and the multidrug-resistance-protein-1 (MRP1). Our aim was to study the time-dependent effect of folate deprivation/supplementation on (i) BCRP and MRP expression and (ii) on drug resistance mediated by these transporters. Therefore Caco-2 colon cancer cells usually grown in standard RPMI-medium containing supraphysiological folic acid (FA) concentrations (2.3 mu M; high-folate, HF) were gradually adapted to more physiological folate concentrations (1 nM leucovorin (LV) or 1 nM FA; low-folate, LF), resulting in the sublines Caco-2-LF/LV and Caco-2-LF/FA. Caco-2-LF/LV and LF/FA cells exhibited a maximal increase of 5.2- and 9.6-fold for BCRP-mRNA and 3.9 and 5.7-fold for BCRP protein expression, respectively, but no major changes on MRP expression. Overexpression of BCRP in the LF-cells resulted in 3.6- to 6.3-fold resistance to mitoxantrone (MR), which was completely reverted by the BCRP inhibitor Ko143. On the other hand, LF-adapted cells were markedly more sensitive to methotrexate than the HF-counterpart, both after 4-hr (9,870- and 23,923-fold for Caco-2-LF/LV and LF/FA, respectively) and 72-hr (11- and 22-fold for Caco-2-LF/LV and LF/FA, respectively) exposure. Immunolluorescent staining observed with a confocal-laser-scan-microscope revealed that in Caco-2 cells (both HF and LF), BCRP is mainly located in the cytoplasm. In conclusion, folate deprivation induces BCRP expression associated with MR resistance in Caco-2 cells. The intracellular localization of BCRP in these cells suggests that this transporter is not primarily extruding its substrates out of the cell, but rather to an intracellular compartment where folates can be kept as storage. (C) 2008 Wiley-Liss. Inc.