title: Down-regulation of human papillomavirus E6/E7 oncogene by arsenic trioxide in cervical carcinoma cells.
abstract: Arsenic trioxide (As2O3) has been implicated as a promising anticancer agent for treatment of many cancers including acute promylocytic leukemia. However, the molecular mechanisms are not yet fully defined in solid tumor cells, especially cervical cancer cells carrying human papillomavirus (HPV) genome. To analyze detailed mechanisms in vitro, we treated As2O3 to transformed HeLa cells, a well-studied cervical cancer cell line carrying HPV-18 sequence, and investigated its antiproliferative, antiviral and antimetastatic effects. As2O3 reduced survival and growth of HeLa cells in a dose- and time-dependent manner. Several indicatives of apoptosis were demonstrated by DNA fragmentation assay, DAPI nuclear staining and FACS analysis, respectively. Protein levels of p53 and cleavage of poly(ADP)-ribose polymerase were increased in a dose-dependent manner following treatment of As2O3. In parallel, semi-quantitative reverse transcription-polymerase chain reaction showed that the treatment inhibited HPV-18 E6/E7 viral gene expression in HeLa cells. Using transient transfection and CAT ELISA, we also found that AP-1 sites, located proximal to HPV-18 upstream regulatory region (URR) promoter, could be the major target sites for As2O3. Furthermore, As2O3-treated HeLa cells showed lesser capacity of invasion than those of untreated cells by in vitro invasion assay. Taken together, we proposed that antiviral effect, i.e. down-regulation of HPV E6/E7 oncogenes through targeting for AP-1 sites located in HPV URR might be associated with antiproliferative effect, i.e. induction of apoptosis as be resulted from the accumulation of p53, and that antimetastatic effect could be due to the targeted inactivation of AP-1, a transcription factor required for the expression of MMP-1 and -3. Therefore, our finding may provide a logical basis for the development of a new agent treating HPV-associated cervical neoplasia.
authors.affiliation: Department of Bioscience and Biotechnology/Institute of Bioscience, Sejong University, Seoul 143-747, South Korea.
authors.forename: Soo-Jong
authors.initials: SJ
authors.lastname: Um
authors.forename: So-Young
authors.initials: SY
authors.lastname: Lee
authors.forename: Eun-Joo
authors.initials: EJ
authors.lastname: Kim
authors.forename: Jin
authors.initials: J
authors.lastname: Myoung
authors.forename: Sung-Eun
authors.initials: SE
authors.lastname: Namkoong
authors.forename: Jong-Sup
authors.initials: JS
authors.lastname: Park
mesh_terms: D017209:Apoptosis / Q000187:drug effects; D000077237:Arsenic Trioxide; D001152:Arsenicals / Q000494:pharmacology*; D002455:Cell Division / Q000187:drug effects; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins / Q000378:metabolism; D004268:DNA-Binding Proteins; D015536:Down-Regulation; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006367:HeLa Cells; D006801:Humans; D009361:Neoplasm Invasiveness; D009856:Oncogene Proteins, Viral / Q000235:genetics*; D010087:Oxides / Q000494:pharmacology*; D000071137:Poly (ADP-Ribose) Polymerase-1; D011065:Poly(ADP-ribose) Polymerases; D011506:Proteins / Q000378:metabolism; D018808:Transcription Factor AP-1 / Q000378:metabolism*; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism; D002583:Uterine Cervical Neoplasms / Q000821:virology*
chemical_list: D001152:Arsenicals; C493956:CDKN1A protein, human; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins; D004268:DNA-Binding Proteins; C052603:E6 protein, Human papillomavirus type 18; C052633:E7 protein, Human papillomavirus type 18; D009856:Oncogene Proteins, Viral; D010087:Oxides; D011506:Proteins; D018808:Transcription Factor AP-1; D016159:Tumor Suppressor Protein p53; C499320:PARP1 protein, human; D000071137:Poly (ADP-Ribose) Polymerase-1; D011065:Poly(ADP-ribose) Polymerases; D000077237:Arsenic Trioxide