Antitumor polycyclic acridines. 20. Search for DNA quadruplex binding selectivity in a series of 8,13-dimethylquino[4,3,2-kl]acridinium salts: telomere-targeted agents.

The growth-inhibitory activities of an extensive series of quaternized quino[4,3,2- kl]acridinium salts against tumor cell lines in vitro have been measured and their biological properties interpreted in the light of differential binding to different DNA isoforms. Selectivity for quadruplex DNA binding and stabilization by compounds were explored through an array of methods: UV absorption and fluorescence emission spectroscopy, surface plasmon resonance, and competition dialysis. Quadruplex DNA interaction was further characterized through FRET and DNA polymerase arrest assays.

Antitumor polycyclic acridines. 17. Synthesis and pharmaceutical profiles of pentacyclic acridinium salts designed to destabilize telomeric integrity.

Palladium(0)-mediated Suzuki-Miyaura and Heck transformations have been exploited to provide examples of 8-methylquino[4,3,2-kl]acridines and 8,13-dimethylquino[4,3,2-kl]acridinium iodides bearing bulky saturated (3-acetoxy)propyl or (E)-3-(morpholin-4-yl)-3-oxopropenyl substituents variously in the 3-, 6-, or 10-positions of the pentacyclic nucleus. The pharmacological/pharmaceutical properties of four compounds (4, RHPS4), (5, IH383), (6, RHPS16), and (17, RHPS19) were measured to assess their clinical potential as DNA G-quadruplex-stabilizing/telomerase inhibitory agents. The following properties were measured: stability in tissue culture media in the presence of A549 lung and MCF-7 breast tumor cells, metabolic stability when incubated with rat liver microsomes, and rate of uptake and subcellular location in A549 and MCF-7 cells.

Pharmacodynamics of the G-quadruplex-stabilizing telomerase inhibitor 3,11-difluoro-6,8,13-trimethyl-8H-quino[4,3,2-kl]acridinium methosulfate (RHPS4) in vitro: activity in human tumor cells correlates with telomere length and can be enhanced, or antagonized, with cytotoxic agents.

Telomeric integrity is required to maintain the replicative ability of cancer cells and is a target for the G-quadruplex-stabilizing drug 3,11-difluoro-6,8,13-trimethyl-8H-quino[4,3,2-kl]acridinium methosulfate (RHPS4). We report a senescent-like growth arrest in MCF-7 breast cancer cells, within 14 to 17 days, and a reduction in telomere length (from 5.2 kilobases (kb) to 4.