title: Hypoxia inducible factor-1 mediates upregulation of urokinase-type plasminogen activator receptor gene transcription during hypoxia in cervical cancer cells.
abstract: Hypoxia occurs during development of cervical cancer and is considered to correlate with its invasion. Hypoxia mediates tumor cells to have more invasive property in a variety of cancers. Urokinase plasminogen activator receptor (uPAR) which mediates invasion is considered to be induced by hypoxia. We sought to determine the regulators of uPAR expression during hypoxia in cervical cancer. We showed that cervical cancer cell lines, CaSki and CA, were more invasive under hypoxic condition (1% O2) than under normoxic condition (20% O2) by invasion assays. Using western blot analysis, hypoxia enhanced the endogenous hypoxia-inducible factor (HIF)-1α and uPAR protein expression. uPAR mRNA level was also upregulated by hypoxia using real-time RT-PCR. Overexpression of HIF-1α which is induced by hypoxia activated the transcriptional activity of the uPAR promoter by luciferase assays. HIF-1 protein bound the putative HIF-1 response element on the uPAR promoter using electrophoretic mobility shift analysis, and additional luciferase assays show that this is essential for uPAR transactivation by HIF-1. HIF-1 overexpression enhanced the endogenous uPAR expression and introduction of siRNA for HIF-1α diminishes uPAR expression during hypoxia. These results indicate the upregulation of uPAR by hypoxia in cervical cancer cells is mediated through HIF-1. In cervical cancer tissues, we also demonstrated that uPAR protein expression was detected in cervical cancer but not in normal cervix or cervical intraepithelial neoplasia (CIN) by immunohistopathological staining. Our results provide evidence that regulation of uPAR expression by HIF-1 represents a mechanism for cervical cancer invasion during hypoxia.
authors.affiliation: Department of Obstetrics and Gynecology, Tokyo Medical University, Shinjuku-ku, Tokyo 160-0023, Japan.
authors.forename: Hirotaka
authors.initials: H
authors.lastname: Nishi
authors.affiliation: Department of Obstetrics and Gynecology, Tokyo Medical University, Shinjuku-ku, Tokyo 160-0023, Japan.
authors.forename: Toru
authors.initials: T
authors.lastname: Sasaki
authors.affiliation: Department of Obstetrics and Gynecology, Tokyo Medical University, Shinjuku-ku, Tokyo 160-0023, Japan.
authors.forename: Yuzo
authors.initials: Y
authors.lastname: Nagamitsu
authors.affiliation: Department of Obstetrics and Gynecology, Tokyo Medical University, Shinjuku-ku, Tokyo 160-0023, Japan.
authors.forename: Fumitoshi
authors.initials: F
authors.lastname: Terauchi
authors.affiliation: Department of Anatomic Pathology, Tokyo Medical University, Shinjuku-ku, Tokyo 160-0023, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Nagai
authors.affiliation: Department of Anatomic Pathology, Tokyo Medical University, Shinjuku-ku, Tokyo 160-0023, Japan.
authors.forename: Toshitaka
authors.initials: T
authors.lastname: Nagao
authors.affiliation: Department of Obstetrics and Gynecology, Tokyo Medical University, Shinjuku-ku, Tokyo 160-0023, Japan.
authors.forename: Keiichi
authors.initials: K
authors.lastname: Isaka
mesh_terms: D015687:Cell Hypoxia; D045744:Cell Line, Tumor; D002467:Cell Nucleus / Q000378:metabolism; D003593:Cytoplasm / Q000378:metabolism; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D017930:Genes, Reporter; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000037:antagonists & inhibitors / Q000235:genetics / Q000502:physiology*; D009361:Neoplasm Invasiveness; D009363:Neoplasm Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000502:physiology; D011401:Promoter Regions, Genetic / Q000235:genetics; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D055293:Receptors, Urokinase Plasminogen Activator / Q000096:biosynthesis* / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000235:genetics; D020218:Response Elements; D015533:Transcriptional Activation; D014162:Transfection; D002583:Uterine Cervical Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D002578:Uterine Cervical Dysplasia / Q000235:genetics / Q000378:metabolism
chemical_list: C497442:HIF1A protein, human; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D009363:Neoplasm Proteins; D034741:RNA, Small Interfering; D055293:Receptors, Urokinase Plasminogen Activator; D011993:Recombinant Fusion Proteins