title: NOAD, a novel nitric oxide donor, induces G2/M phase arrest and apoptosis in human hepatocellular carcinoma Bel-7402 cells.
abstract: O(2)-(2,4-dinitro-5-{[2-(12-en-28-b-d-galactopyranosyl-oleanolate-3-yl)-oxy-2-oxoethyl]amino}phenyl)1-(N-hydroxyethylmethylamino)diazen-1-ium-1,2-diolate (NOAD), a novel NO-releasing derivative of oleanolic acid (OA), is an active cytotoxic component. In this study, NOAD induced a rise in intracellular NO levels and showed cytotoxic effects which were prevented by hemoglobin (NO scavenger). Meanwhile, NOAD induced G2/M phase cell cycle arrest in a concentration-dependent manner. Analysis of the cell cycle regulatory proteins demonstrated that NOAD did not change the steady-state levels of cyclin A, cyclin B, cyclin E, Cdk2 and Cdk4, but decreased the protein levels of Cdk1 and Cdc25C. Meanwhile, the levels of phosphorylation of Cdc25C and Cdk1 were significantly increased by NOAD in a concentration-dependent manner. Moreover, NOAD modulated the phosphorylation of protein kinases Chk2. During the G2/M arrest, cyclin-dependent kinase inhibitors (CDKIs), p21(WAF1/CIP1) and p27(kip1) were increased in a concentration-dependent manner. In addition, NOAD also caused a marked increase in the apoptotic cells, as characterized by fragmented nuclei, sub G1 formation, the level of 8-OHDG increase and poly (ADP-ribose) polymerase (PARP) cleavage, which was associated with activation of caspase-3, caspase-8 and caspase-9. Up-regulation of Bax and down-regulation of Bcl-2 were also observed in Bel-7402 cells treated with NOAD. These data suggest that NOAD produces anti-tumor effect via induction of G2/M cell cycle arrest and apoptosis.
authors.affiliation: Department of Pharmacy, Medical College, Henan University of Science and Technology, Luoyang 471003, China.
authors.forename: Ling
authors.initials: L
authors.lastname: Liu
authors.affiliation: Department of Pathogen Biology, Medical College, Henan University of Science and Technology, Luoyang 471003, China.
authors.forename: Dongmei
authors.initials: D
authors.lastname: Wang
authors.affiliation: Department of Pharmacy, Medical College, Henan University of Science and Technology, Luoyang 471003, China.
authors.forename: Jiangang
authors.initials: J
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Natural Medicines, Department of Pharmacology, China Pharmaceutical University, Nanjing 210009, China. Electronic address: jihuicpu@163.com.
authors.forename: Hui
authors.initials: H
authors.lastname: Ji
authors.affiliation: Center of Drug Discovery, China Pharmaceutical University, Nanjing 210009, China. Electronic address: zyhtgd@sohu.com.
authors.forename: Yihua
authors.initials: Y
authors.lastname: Zhang
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D001391:Azo Compounds / Q000494:pharmacology*; D006528:Carcinoma, Hepatocellular / Q000378:metabolism; D020169:Caspases / Q000378:metabolism; D059447:Cell Cycle Checkpoints / Q000187:drug effects; D018797:Cell Cycle Proteins / Q000378:metabolism; D002455:Cell Division / Q000187:drug effects; D045744:Cell Line, Tumor; D016195:G2 Phase / Q000187:drug effects; D006801:Humans; D008113:Liver Neoplasms / Q000378:metabolism; D020030:Nitric Oxide Donors / Q000494:pharmacology*; D012503:Saponins / Q000494:pharmacology*
chemical_list: D000970:Antineoplastic Agents; D001391:Azo Compounds; D018797:Cell Cycle Proteins; D020030:Nitric Oxide Donors; C000608116:O(2)-(2,4-dinitro-5-((2-(12-en-28-galactopyranosyloleanolate-3-yl)-oxy-2-oxoethyl)amino)phenyl)1-(N-hydroxyethylmethylamino)diazen-1-ium-1,2-diolate; D012503:Saponins; D020169:Caspases
keywords: Apoptosis; G2/M arrest; Human hepatocellular carcinoma; Nitric oxide