title: Isoliquiritigenin induces G2 and M phase arrest by inducing DNA damage and by inhibiting the metaphase/anaphase transition.
abstract: Isoliquiritigenin, a natural flavonoid found in licorice, shallots, and bean sprouts, has been demonstrated to inhibit proliferation and to induce apoptosis in a variety of human cancer cells. We attempted to ascertain the underlying mechanism by which isoliquiritigenin induced cell cycle arrest and cytotoxicity in HeLa human cervical cancer cells. Isoliquiritigenin treatment arrested cells in both G2 and M phase. The cells arrested in interphase (G2) showed markers for DNA damage including the formation of gamma-H2AX foci and the phosphorylation of ATM and Chk2, whereas the cells arrested in M phase evidenced separate poles and mitotic metaphase-like spindles with partially unaligned chromosomes. The induction of DNA damage and blockade at the metaphase/anaphase transition implied that isoliquiritigenin might function as a topoisomerase II poison, which was further demonstrated via an in vitro topoisomerase II inhibition assay. These results show that isoliquiritigenin inhibits topoiosmerase II activity, and the resultant DNA damage and arrest in mitotic metaphase-like stage contributes to the antiproliferative effects of isoliquiritigenin.
authors.affiliation: Oral Cancer Research Institute, Yonsei University College of Dentistry, Seoul, Republic of Korea.
authors.forename: Iha
authors.initials: I
authors.lastname: Park
authors.forename: Kwang-Kyun
authors.initials: KK
authors.lastname: Park
authors.forename: Jung Han Yoon
authors.initials: JH
authors.lastname: Park
authors.forename: Won-Yoon
authors.initials: WY
authors.lastname: Chung
mesh_terms: D000705:Anaphase / Q000187:drug effects* / Q000502:physiology; D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology*; D064007:Ataxia Telangiectasia Mutated Proteins; D018797:Cell Cycle Proteins / Q000378:metabolism; D047188:Chalcones / Q000494:pharmacology*; D064447:Checkpoint Kinase 2; D004249:DNA Damage / Q000187:drug effects* / Q000502:physiology; D004250:DNA Topoisomerases, Type II / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism; D016195:G2 Phase / Q000187:drug effects* / Q000502:physiology; D006367:HeLa Cells; D006657:Histones / Q000378:metabolism; D006801:Humans; D008677:Metaphase / Q000187:drug effects* / Q000502:physiology; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D025521:Tumor Suppressor Proteins / Q000378:metabolism
chemical_list: D000972:Antineoplastic Agents, Phytogenic; D018797:Cell Cycle Proteins; D047188:Chalcones; D004268:DNA-Binding Proteins; C468783:H2AX protein, human; D006657:Histones; D025521:Tumor Suppressor Proteins; C040920:isoliquiritigenin; D064447:Checkpoint Kinase 2; C576324:ATM protein, human; D064007:Ataxia Telangiectasia Mutated Proteins; C578634:CHEK2 protein, human; D017346:Protein Serine-Threonine Kinases; D004250:DNA Topoisomerases, Type II