Muñoz-Martínez Francisco, Reyes Carolina P, Pérez-Lomas Antonio L, Jiménez Ignacio A, Gamarro Francisco, Castanys Santiago
Instituto de Parasitología y Biomedicina López-Neyra, Consejo Superior de Investigaciones Científicas, Parque Tecnológico de Ciencias de la Salud, Avenida del Conocimiento s/n, 18100 Armilla, Granada, Spain.
Biochim Biophys Acta. 2006 Jan;1758(1):98-110. doi: 10.1016/j.bbamem.2005.12.006. Epub 2006 Jan 11.
Dihydro-beta-agarofuran sesquiterpenes from Celastraceae have been recently shown to bind to human P-glycoprotein (Pgp), functioning as specific, mixed-type inhibitors of its drug transport activity, as well as multidrug resistance (MDR) modulators in vitro. However, nothing is known about whether such compounds are themselves transported by Pgp, or whether they affect Pgp expression as well as its activity, or about the location of their binding site within the protein. We performed transport experiments with a newly synthesized fluorescent sesquiterpene derivative, which retains the anti-Pgp activity of its natural precursor. This probe was poorly transported by Pgp, MRP1, MRP2 and BCRP transporters, compared with classical MDR substrates. Moreover, Pgp did not confer cross-resistance to the most potent dihydro-beta-agarofurans, which did not affect Pgp expression levels in several MDR cell lines. Finally, we observed competitive and non-competitive interactions between one of such dihydro-beta-agarofurans (Mama12) and classical Pgp modulators such as cyclosporin A, verapamil, progesterone, vinblastine and GF120918. These findings suggest that multidrug ABC transporters do not confer resistance to dihydro-beta-agarofurans and could not affect their absorption and biodistribution in the body. Moreover, we mapped their binding site(s) within Pgp, which may prove useful for the rational design of improved modulators based on the structure of dihydro-beta-agarofurans.
最近研究表明，卫矛科植物中的二氢-β-琼脂呋喃倍半萜可与人类P-糖蛋白（Pgp）结合，作为其药物转运活性的特异性混合型抑制剂以及体外多药耐药（MDR）调节剂发挥作用。然而，对于这类化合物自身是否会被Pgp转运，是否会影响Pgp的表达及其活性，以及它们在蛋白质中的结合位点位置，目前尚不清楚。我们用一种新合成的荧光倍半萜衍生物进行了转运实验，该衍生物保留了其天然前体的抗Pgp活性。与经典的MDR底物相比，这种探针被Pgp、多药耐药相关蛋白1（MRP1）、多药耐药相关蛋白2（MRP2）和乳腺癌耐药蛋白（BCRP）转运的能力较弱。此外，Pgp并未赋予对最有效的二氢-β-琼脂呋喃的交叉耐药性，这些二氢-β-琼脂呋喃也不影响几种MDR细胞系中Pgp的表达水平。最后，我们观察到其中一种二氢-β-琼脂呋喃（Mama12）与环孢素A、维拉帕米、孕酮、长春碱和GF120918等经典Pgp调节剂之间存在竞争性和非竞争性相互作用。这些发现表明，多药ABC转运蛋白不会赋予对二氢-β-琼脂呋喃的耐药性，也不会影响它们在体内的吸收和生物分布。此外，我们确定了它们在Pgp中的结合位点，这可能有助于基于二氢-β-琼脂呋喃的结构合理设计出改进的调节剂。
