Weak base permeability characteristics influence the intracellular sequestration site in the multidrug-resistant human leukemic cell line HL-60
Weak base permeability characteristics influence the intracellular sequestration site in the multidrug-resistant human leukemic cell line HL-60
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DOI：
10.1074/jbc.m400735200
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发表时间：
2004-07-30
影响因子：
4.8
通讯作者：
Krise, JP
中科院分区：
文献类型：
--
作者：
Duvvuri, M;Gong, YP;Krise, JP
哺乳动物细胞中的一些细胞器与包括药物分子在内的化学实体的选择性隔离有关。具体地说，弱碱性分子被证明选择性地与线粒体或溶酶体结合；然而，这种分化的结构基础尚不清楚。为了研究这一点，我们已经鉴定了一系列七种弱碱性化合物，它们都具有接近中性的PK(α)，它们在多药耐药的HL-60人白血病细胞系中具有不同的隔离位置。其中三种化合物被选择性地隔离在细胞的线粒体中，而其余的主要定位于溶酶体中。使用特定的化学抑制剂来破坏线粒体或溶酶体的积累能力，我们证明了这些化合物在各自细胞器中的积累不是竞争性的过程。比较这些化合物的通透性随pH的变化特征，发现与细胞内隔离位置相关的显著差异。只有那些在电离状态下与非电离状态相比通透性显著降低的化合物才有能力在溶酶体中积累。或者，那些对pH相对不敏感的渗透性化合物选择性地积聚到线粒体中。使用新的定量方法来检测药物在亚细胞细胞器中的积累，我们证明了这些通透性特征与这些化合物的溶酶体和线粒体积累能力之间的相关性。综上所述，这些结果表明，弱碱性化合物在溶酶体和线粒体中的选择性积累是通过一个独特的通透性参数控制的专有途径发生的。
A number of organelles contained within mammalian cells have been implicated in the selective sequestration of chemical entities including drug molecules. Specifically, weakly basic molecules have been shown to selectively associate with either the mitochondrial compartment or lysosomes; however, the structural basis for this differentiation has not been understood. To investigate this, we have identified a series of seven weakly basic compounds, all with pK(alpha) near neutrality, which have different sequestration sites within the multidrug-resistant HL-60 human leukemic cell line. Three of the compounds were selectively sequestered into the mitochondria of the cells, whereas the remainder were predominantly localized within lysosomes. Using specific chemical inhibitors to disrupt either mitochondrial or lysosomal accumulation capacity, we demonstrated that accumulation of these compounds into respective organelles are not competitive processes. Comparison of the permeability characteristics of these compounds as a function of pH revealed striking differences that correlate with the intracellular sequestration site. Only those compounds with significantly reduced permeability in the ionized state relative to the un-ionized state had the capacity to accumulate within lysosomes. Alternatively, those compounds with relatively pH-insensitive permeability selectively accumulated into mitochondria. Using novel quantitative assays for assaying drug accumulation into subcellular organelles, we demonstrated a correlation between these permeability characteristics and the lysosomal versus mitochondrial accumulation capacity of these compounds. Together, these results suggest that the selective accumulations of weakly basic compounds in either lysosomes and mitochondria occur via exclusive pathways governed by a unique permeability parameter.