Advanced Technology Research Laboratories, Panasonic Corporation, 3-4 Hikaridai, Seika-cho, Soraku-gun, Kyoto 619-0237, Japan.
J Phys Chem B. 2014 Mar 13;118(10):2605-14. doi: 10.1021/jp410669t. Epub 2013 Dec 20.
G-quadruplex-binding and telomerase-inhibiting capacities of G-quadruplex ligands were examined under a cell nuclei-mimicking condition including excess double-stranded DNA (λ DNA) and molecular crowding cosolute (PEG 200). Under the cell nuclei-mimicking condition, a cationic porphyrin (TMPyP4) did not bind to the G-quadruplex despite the high affinity (Ka = 3.6 × 10(6) M(-1)) under a diluted condition without λ DNA and PEG 200. Correspondingly, TMPyP4 inhibited telomerase activity under the diluted condition (IC50 = 1.6 μM) but not under the cell nuclei-mimicking condition. In contrast, the Ka and IC50 values of an anionic copper phthalocyanine (Cu-APC) under the diluted (2.8 × 10(4) M(-1) and 0.86 μM) and the cell nuclei-mimicking (2.8 × 10(4) M(-1) and 2.1 μM) conditions were similar. In accordance with these results, 10 μM TMPyP4 did not affect the proliferation of HeLa cells, while Cu-APC efficiently inhibited the proliferation (IC50 = 1.4 μM). These results show that the cell nuclei-mimicking condition is effective to predict capacities of G-quadruplex ligands in the cell. In addition, the antiproliferative effect of Cu-APC on normal cells was smaller than that on HeLa cells, indicating that the cell nuclei-mimicking condition is also useful to predict side effects of ligands.
在包括过量双链 DNA（λ DNA）和分子拥挤共溶质（PEG 200）的模拟细胞核条件下，研究了 G-四链体结合和端粒酶抑制能力的 G-四链体配体。在模拟细胞核条件下，尽管阳离子卟啉（TMPyP4）在没有 λ DNA 和 PEG 200 的稀释条件下具有高亲和力（Ka=3.6×10^6 M^-1），但它没有与 G-四链体结合。相应地，TMPyP4 在稀释条件下抑制端粒酶活性（IC50=1.6 μM），但在模拟细胞核条件下没有抑制。相比之下，阴离子铜酞菁（Cu-APC）在稀释（2.8×10^4 M^-1 和 0.86 μM）和模拟细胞核（2.8×10^4 M^-1 和 2.1 μM）条件下的 Ka 和 IC50 值相似。根据这些结果，10 μM TMPyP4 不会影响 HeLa 细胞的增殖，而 Cu-APC 则有效地抑制了增殖（IC50=1.4 μM）。这些结果表明，模拟细胞核条件可有效预测 G-四链体配体在细胞中的能力。此外，Cu-APC 对正常细胞的增殖抑制作用小于对 HeLa 细胞的抑制作用，表明模拟细胞核条件也可用于预测配体的副作用。
