title: In vitro assays predictive of telomerase inhibitory effect of G-quadruplex ligands in cell nuclei.
abstract: 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.
authors: Advanced Technology Research Laboratories, Panasonic Corporation, 3-4 Hikaridai, Seika-cho, Soraku-gun, Kyoto 619-0237, Japan.
authors: Hidenobu
authors: H
authors: Yaku
authors: Takashi
authors: T
authors: Murashima
authors: Daisuke
authors: D
authors: Miyoshi
authors: Naoki
authors: N
authors: Sugimoto
mesh_terms: D002467:Cell Nucleus / Q000378:metabolism*; D049109:Cell Proliferation / Q000187:drug effects; D004247:DNA / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D054856:G-Quadruplexes; D006367:HeLa Cells; D006801:Humans; D007211:Indoles / Q000494:pharmacology; D008024:Ligands; D050258:Mitosis Modulators / Q000494:pharmacology; D008954:Models, Biological; D009942:Organometallic Compounds / Q000494:pharmacology; D011092:Polyethylene Glycols / Q000378:metabolism; D011166:Porphyrins / Q000378:metabolism; D055672:Static Electricity; D019098:Telomerase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D016615:Telomere / Q000378:metabolism
chemical_list: D004791:Enzyme Inhibitors; D007211:Indoles; D008024:Ligands; D050258:Mitosis Modulators; D009942:Organometallic Compounds; D011166:Porphyrins; C021096:tetra(4-N-methylpyridyl)porphine; C015445:copper phthalocyanine; D011092:Polyethylene Glycols; D004247:DNA; D019098:Telomerase