title: Apoptosis related to telomere instability and cell cycle alterations in human glioma cells treated by new highly selective G-quadruplex ligands.
abstract: Telomerase represents a relevant target for cancer therapy. Molecules able to stabilize the G-quadruplex (G4), a structure adopted by the 3'-overhang of telomeres, are thought to inhibit telomerase by blocking its access to telomeres. We investigated the cellular effects of four new 2,6-pyridine-dicarboxamide derivatives displaying strong selectivity for G4 structures and strong inhibition of telomerase in in vitro assays. These compounds inhibited cell proliferation at very low concentrations and then induced a massive apoptosis within a few days in a dose-dependent manner in cultures of three telomerase-positive glioma cell lines, T98G, CB193 and U118-MG. They had also antiproliferative effects in SAOS-2, a cell line in which telomere maintenance involves an alternative lengthening of telomeres (ALT) mechanism. We show that apoptosis was preceded by multiple alterations of the cell cycle: activation of S-phase checkpoints, dramatic increase of metaphase duration and cytokinesis defects. These effects were not associated with telomere shortening, but they were directly related to telomere instability involving telomere end fusion and anaphase bridge formation. Pyridine-based G-quadruplex ligands are therefore promising agents for the treatment of various tumors including malignant gliomas.
authors.affiliation: Laboratoire de Radiopathologie, DSV/DRR, CEA, 18 route du Panorama, 92265 Fontenay-aux-Roses, France.
authors.forename: Gaëlle
authors.initials: G
authors.lastname: Pennarun
authors.forename: Christine
authors.initials: C
authors.lastname: Granotier
authors.forename: Laurent R
authors.initials: LR
authors.lastname: Gauthier
authors.forename: Dennis
authors.initials: D
authors.lastname: Gomez
authors.forename: Françoise
authors.initials: F
authors.lastname: Hoffschir
authors.forename: Eliane
authors.initials: E
authors.lastname: Mandine
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Riou
authors.forename: Jean-Louis
authors.initials: JL
authors.lastname: Mergny
authors.forename: Patrick
authors.initials: P
authors.lastname: Mailliet
authors.forename: François D
authors.initials: FD
authors.lastname: Boussin
mesh_terms: D017209:Apoptosis / Q000502:physiology*; D002453:Cell Cycle; D002455:Cell Division / Q000235:genetics / Q000276:immunology; D042822:Genomic Instability / Q000502:physiology*; D005910:Glioma / Q000188:drug therapy; D006801:Humans; D008024:Ligands; D011725:Pyridines / Q000494:pharmacology; D019098:Telomerase / Q000037:antagonists & inhibitors; D016615:Telomere / Q000235:genetics* / Q000378:metabolism*
chemical_list: D008024:Ligands; D011725:Pyridines; D019098:Telomerase