|Senescence and telomere shortening induced by novel potent G-quadruplex interactive agents, quindoline derivatives, in human cancer cell lines|
Zhou JM, Zhu XF, Lu YJ, Deng R, Huang ZS, Mei YP, Wang Y, Huang WL, Liu ZC, Gu LQ, Zeng YX
Category: telomerase, telomere ¤ Added: Jan 30, 2006 ¤ Rating: ◊◊
Agents stabilizing G-quadruplexes have the potential to interfere with telomere replication by blocking the elongation step catalysed by telomerase or telomerase-independent mechanism and could therefore act as antitumor agents. In this study, we found that quindoline derivatives interacted preferentially with intramolecular G-quadruplex structures and were novel potent telomerase inhibitors. Treatment with quindoline derivatives reproducibly inhibited telomerase activity in human leukemia K562 cells and colon cancer SW620 cells. N0-(10H-Indolo [3,2-b] quinolin-11-yl)-N, Ndimethyl- propane-1,3-diamine (SYUIQ-5), (one of quindoline derivatives), when added to K562 and SW620 cell culture at nonacute cytotoxic concentrations, increased time of population doublings of K562 and SW620 cells, induced a marked cessation in cell growth and cellular senescence phenotype after 35 and 18 days, respectively. Growth cessation was accompanied by a shortening of telomere length, and induction of p16, p21 and p27 protein expression. However, another compound SYUIQ-7 with greater IC50 for telomerase had no obvious cellular effect in nonacute cytotoxic concentrations. These results indicate that quindoline derivatives as novel potent G-quadruplex interactive agents induce senescence and telomere shortening in cancer cells and therefore are promising agents for cancer treatment.