Department of Clinical Pharmacology and Pharmacoepidemiology, University of Heidelberg, Im Neuenheimer Feld 410, 69120, Heidelberg, Germany.
Institute of Experimental Physiology (IFISE-CONICET), Suipacha 570, 2000, Rosario, Argentina.
Eur J Nutr. 2019 Feb;58(1):139-150. doi: 10.1007/s00394-017-1578-9. Epub 2017 Nov 3.
The soy isoflavone genistein has been described to up-regulate breast cancer resistance protein (BCRP) and, thus, enhance chemoresistance in breast cancer cells. The aim of this work was to assess the effect of long- and short-term incubation with daidzein, the second most abundant soy isoflavone and its metabolite equol on the expression and activity of P-glycoprotein, multidrug resistance-associated proteins 1 and 2 (MRP1 and MRP2) and BCRP in breast cancer cells.
MCF-7 and MDA-MB-231 cells were treated with phytoestrogen concentrations within the range achieved in individuals with a high isoflavone intake. Transporter expression was evaluated at protein and mRNA level through western blot and qRT-PCR, respectively. Transporter activity was determined using doxorubicin, mitoxantrone and carboxy-dichlorofluorescein as substrates.
Daidzein (5 µM) up-regulated MRP2- and down-regulated MRP1 protein expressions in MCF-7 and MDA-MB-231 cells, respectively. Both effects were ER-dependent, as determined using the antagonist ICI 182,780. The decrease in MRP1 mRNA in MDA-MB-231 cells indicates a transcriptional mechanism. On the contrary, MRP2 induction in MCF-7 cells takes place post-transcriptionally. Whereas changes in the transporter expression had a minor effect on the transporter activity, acute incubation with daidzein, R-equol and S-equol led to a strong inhibition of BCRP activity and an increase in the IC of BCRP substrates.
In contrast to previous reports for genistein, daidzein and equol do not provoke a major up-regulation of the transporter expression but instead an inhibition of BCRP activity and sensitization to BCRP substrates.
大豆异黄酮染料木黄酮已被描述为上调乳腺癌耐药蛋白（BCRP），从而增强乳腺癌细胞的化疗耐药性。本研究旨在评估长期和短期孵育大豆异黄酮中第二丰富的染料木黄酮及其代谢物雌马酚对乳腺癌细胞中 P-糖蛋白、多药耐药相关蛋白 1 和 2（MRP1 和 MRP2）和 BCRP 的表达和活性的影响。
用植物雌激素浓度处理 MCF-7 和 MDA-MB-231 细胞，该浓度范围在高异黄酮摄入量个体中可达到。通过 Western blot 和 qRT-PCR 分别在蛋白和 mRNA 水平评估转运蛋白表达。使用阿霉素、米托蒽醌和羧基-二氯荧光素作为底物测定转运蛋白活性。
染料木黄酮（5 μM）分别上调 MCF-7 和 MDA-MB-231 细胞中的 MRP2-并下调 MRP1 蛋白表达。这两种作用均依赖于 ER，这是通过使用拮抗剂 ICI 182,780 确定的。MDA-MB-231 细胞中 MRP1 mRNA 的减少表明存在转录机制。相反，MRP2 在 MCF-7 细胞中的诱导发生在转录后。尽管转运蛋白表达的变化对转运蛋白活性的影响较小，但急性孵育染料木黄酮、R-雌马酚和 S-雌马酚会强烈抑制 BCRP 活性并增加 BCRP 底物的 IC。
与先前关于染料木黄酮和雌马酚的报道相反，它们不会引起转运蛋白表达的主要上调，而是抑制 BCRP 活性并使 BCRP 底物敏感。
