[Telomerase inhibitor, telomestatin, a specific mechanism to interact with telomere structure]

A novel telomerase inhibitor, telomestatin, isolated from Streptomyces anulatus is the most potent telomerase inhibitor so far. Telomestatin specifically inhibited telomerase without affecting reverse transcriptases and polymerases. In addition, telomestatin induced telomere shortening, but its ratio was extremely faster than that observed in physiological telomere shortening. These results suggested the existence of other mechanisms to inhibit telomerase. Telomeres consist of guanine rich sequences which compose a characteristic three-dimensional structure designated as G-quadruplex. Stabilization of G-quadruplex structure inhibited the catalysis of not only telomerase but also other DNA interacting molecules. Telomestatin potently stabilized G-quadruplex structure in a specific manner. G-quadruplex structure is also involved in a lot of oncogene promoters. Thus, telomestatin provide the novel therapeutic molecular target for cancer chemotherapy.