Abstract：
Red fluorescent dyes are usually charged, lypophilic molecules with the relatively high molecular weight, which tend to localize in specific intracellular locations, e.g., a cyanine dye Cy5 is biased towards mitochondria. They are often used as markers of biomolecules including nucleic acids and proteins. Since molecular weight of the dyes is much smaller than that of the biomolecules, the labelling has a negligible effect on the properties of the biomolecules. In contrast, conjugation of the dyes to low molecular weight (pro)drugs can dramatically alter their properties. For example, conjugates of Cy5 with lysosome-targeting aminoferrocenes accumulate in mitochondria and exhibit no intracellular effects characteristic for the parent (pro)drugs. Herein we tested several neutral and negatively charged dyes for labelling lysosome-targeting aminoferrocenes 7 and 8 as well as a non-targeted control 3. We found that a BODIPY derivative BDP-TR exhibits the desired unbiased properties: the conjugation does not disturb the intracellular localization of the (pro)drugs, their mode of action and cancer cell specificity. We used the conjugates to clarify the mechanism of action of the aminoferrocenes. In particular, we identified new intermediates, explained why lysosome targeting aminoferrocenes are more potent than their non-targeted counterparts and evaluated their distribution in vivo.
摘要：
红色荧光染料通常带电荷，具有相对高分子量的亲脂性分子，倾向于定位在特定的细胞内位置，例如，花青染料Cy5偏向线粒体。它们通常用作生物分子(包括核酸和蛋白质)的标记。由于染料的分子量比生物分子的分子量小得多，标记对生物分子的性质具有可忽略的影响。相比之下,染料与低分子量（前体）药物的结合可以显着改变其性质。例如,Cy5与溶酶体靶向氨基二茂铁的缀合物在线粒体中积累，并且没有表现出母体（前体）药物特有的细胞内作用。在此,我们测试了几种中性和带负电荷的染料,用于标记溶酶体靶向氨基二茂铁7和8以及非靶向对照3。我们发现BODIPY衍生物BDP-TR具有所需的无偏性质：缀合不会干扰（前体）药物的细胞内定位，它们的作用方式和癌细胞特异性。我们使用缀合物来阐明氨基二茂铁的作用机理。特别是,我们确定了新的中间体，解释了为什么溶酶体靶向氨基二茂铁比它们的非靶向对应物更有效，并评估了它们在体内的分布。
