title: G-quadruplexes induce apoptosis in tumor cells.
abstract: Several G-rich oligodeoxynucleotides (ODNs), which are capable of forming G-quadruplexes, have been shown to exhibit antiproliferative activity against tumor cell lines and antitumor activity in nude mice carrying prostate and breast tumor xenografts. However, the molecular basis for their antitumor activity remains unclear. In the current study, we showed that a variety of telomeric G-tail oligodeoxynucleotides (TG-ODNs) exhibited antiproliferative activity against many tumor cells in culture. Systematic mutational analysis of the TG-ODNs suggests that the antiproliferative activity depends on the G-quadruplex conformation of these TG-ODNs. TG-ODNs were also shown to induce poly(ADP-ribose) polymerase-1 cleavage, phosphatidylserine flipping, and caspase activation, indicative of induction of apoptosis. TG-ODN-induced apoptosis was largely ataxia telangiectasia mutated (ATM) dependent. Furthermore, TG-ODN-induced apoptosis was inhibited by the c-Jun NH(2)-terminal kinase (JNK) inhibitor SP600125. Indeed, TG-ODNs were shown to activate the JNK pathway in an ATM-dependent manner as evidenced by elevated phosphorylation of JNK and c-Jun. Interestingly, a number of G-quadruplex ODNs (GQ-ODN) derived from nontelomeric sequences also induced ATM/JNK-dependent apoptosis, suggesting a possible common mechanism of tumor cell killing by GQ-ODNs.
authors.affiliation: Department of Pharmacology, University of Medicine and Dentistry of New Jersey, Robert Wood Johnson Medical School, Piscataway, New Jersey 08854, USA. qiha@umdnj.edu
authors.forename: Haiyan
authors.initials: H
authors.lastname: Qi
authors.forename: Chao-Po
authors.initials: CP
authors.lastname: Lin
authors.forename: Xuan
authors.initials: X
authors.lastname: Fu
authors.forename: Laurence M
authors.initials: LM
authors.lastname: Wood
authors.forename: Angela A
authors.initials: AA
authors.lastname: Liu
authors.forename: Yuan-Chin
authors.initials: YC
authors.lastname: Tsai
authors.forename: Yongjie
authors.initials: Y
authors.lastname: Chen
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Barbieri
authors.forename: Daniel S
authors.initials: DS
authors.lastname: Pilch
authors.forename: Leroy F
authors.initials: LF
authors.lastname: Liu
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology*; D001483:Base Sequence; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects*; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects / Q000502:physiology; D006801:Humans; D008168:Lung; D051379:Mice; D009838:Oligodeoxyribonucleotides / Q000494:pharmacology*; D016615:Telomere / Q000502:physiology*
chemical_list: D009838:Oligodeoxyribonucleotides