title: Zoledronate-induced S phase arrest and apoptosis accompanied by DNA damage and activation of the ATM/Chk1/cdc25 pathway in human osteosarcoma cells.
abstract: Osteosarcoma is one of the most common primary malignant tumors of the bone in children and adolescents. Some patients continue to have a poor prognosis, as they have metastatic disease and frequent occurrence of drug resistance. Zoledronate is a nitrogen-containing bisphosphonate that has been used for the treatment of hypercalcemia and bone metastasis, because it induces apoptosis in osteoclasts and tumor cells by inhibiting the isoprenylation of intracellular small G proteins. Besides inhibiting isoprenylation, little is known about the manner by which bisphosphonates inhibit cellular proliferation and induce apoptosis. This prompted us to investigate the inhibitory effects of zoledronate in human osteosarcoma cell lines, HOS and MG63. HOS cells accumulated in S phase around 6 h after treatment with 10 microM zoledronate, followed by apoptosis. When HOS cells were treated with zoledronate, ATM kinase and its substrate, check-point kinase (Chk)1, were phosphorylated. Zoledronate also induced phosphorylation of cdc25a (Thr506) in HOS cells, which is a substrate of Chk1, and its phosphorylation is known to be critical for S phase arrest. Following treatment with zoledronate, phosphorylated histone H2AX (gamma-H2AX) displayed patterns of nuclear foci in HOS cells. As gamma-H2AX accumulates at dsDNA breaks, these results demonstrate that zoledronate induced DNA damage and S phase arrest, accompanied by activation of the ATM/Chk1/cdc25 pathway in a human osteosarcoma cell line.
authors.affiliation: Division of Hematology, Department of Internal Medicine, Keio University School of Medicine, Tokyo 160-8582, Japan.
authors.forename: Toyotaka
authors.initials: T
authors.lastname: Iguchi
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Miyakawa
authors.forename: Kaori
authors.initials: K
authors.lastname: Saito
authors.forename: Chika
authors.initials: C
authors.lastname: Nakabayashi
authors.forename: Makoto
authors.initials: M
authors.lastname: Nakanishi
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Saya
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Ikeda
authors.forename: Masahiro
authors.initials: M
authors.lastname: Kizaki
mesh_terms: D017209:Apoptosis; D064007:Ataxia Telangiectasia Mutated Proteins; D050071:Bone Density Conservation Agents / Q000494:pharmacology*; D001859:Bone Neoplasms / Q000188:drug therapy*; D018797:Cell Cycle Proteins / Q000378:metabolism*; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D000071877:Checkpoint Kinase 1; D004249:DNA Damage; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004164:Diphosphonates / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D006801:Humans; D007093:Imidazoles / Q000494:pharmacology*; D012516:Osteosarcoma / Q000188:drug therapy*; D011494:Protein Kinases / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D016196:S Phase / Q000187:drug effects*; D015398:Signal Transduction; D025521:Tumor Suppressor Proteins / Q000378:metabolism*; D000077211:Zoledronic Acid; D020687:cdc25 Phosphatases / Q000378:metabolism*
chemical_list: D050071:Bone Density Conservation Agents; D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D004164:Diphosphonates; D007093:Imidazoles; D025521:Tumor Suppressor Proteins; D000077211:Zoledronic Acid; D011494:Protein Kinases; C576324:ATM protein, human; D064007:Ataxia Telangiectasia Mutated Proteins; C000605867:CHEK1 protein, human; D000071877:Checkpoint Kinase 1; D017346:Protein Serine-Threonine Kinases; C517009:CDC25C protein, human; D020687:cdc25 Phosphatases