title: hypoxia-inducible factors activate CD133 promoter through ETS family transcription factors.
abstract: CD133 is a cellular surface protein that has been reported to be a cancer stem cell marker, and thus it is considered to be a potential target for cancer treatment. However, the mechanism regulating CD133 expression is not yet understood. In this study, we analyzed the activity of five putative promoters (P1-P5) of CD133 in human embryonic kidney (HEK) 293 cells and colon cancer cell line WiDr, and found that the activity of promoters, particularly of P5, is elevated by overexpression of hypoxia-inducible factors (HIF-1α and HIF-2α). Deletion and mutation analysis identified one of the two E-twenty six (ETS) binding sites (EBSs) in the P5 region as being essential for its promoter activity induced by HIF-1α and HIF-2α. In addition, a chromatin imunoprecipitation assay demonstrated that HIF-1α and HIF-2α bind to the proximal P5 promoter at the EBSs. The immunoprecipitation assay showed that HIF-1α physically interacts with Elk1; however, HIF-2α did not bind to Elk1 or ETS1. Furthermore, knockdown of both HIF-1α and HIF-2α resulted in a reduction of CD133 expression in WiDr. Taken together, our results revealed that HIF-1α and HIF-2α activate CD133 promoter through ETS proteins.
authors.affiliation: Department of Gastroenterology and Hepatology, Hokkaido University Graduate School of Medicine, Sapporo, Japan. sonishi@pop.med.hokudai.ac.jp
authors.forename: Shunsuke
authors.initials: S
authors.lastname: Ohnishi
authors.forename: Osamu
authors.initials: O
authors.lastname: Maehara
authors.forename: Koji
authors.initials: K
authors.lastname: Nakagawa
authors.forename: Ayano
authors.initials: A
authors.lastname: Kameya
authors.forename: Kanako
authors.initials: K
authors.lastname: Otaki
authors.forename: Hirotoshi
authors.initials: H
authors.lastname: Fujita
authors.forename: Ryosuke
authors.initials: R
authors.lastname: Higashi
authors.forename: Kikuko
authors.initials: K
authors.lastname: Takagi
authors.forename: Masahiro
authors.initials: M
authors.lastname: Asaka
authors.forename: Naoya
authors.initials: N
authors.lastname: Sakamoto
authors.forename: Masanobu
authors.initials: M
authors.lastname: Kobayashi
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Takeda
mesh_terms: D000071916:AC133 Antigen; D015703:Antigens, CD / Q000235:genetics* / Q000378:metabolism; D051792:Basic Helix-Loop-Helix Proteins / Q000502:physiology*; D001665:Binding Sites; D015687:Cell Hypoxia; D045744:Cell Line, Tumor; D015870:Gene Expression; D055785:Gene Knockdown Techniques; D006023:Glycoproteins / Q000235:genetics* / Q000378:metabolism; D057809:HEK293 Cells; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000502:physiology*; D010455:Peptides / Q000235:genetics* / Q000378:metabolism; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D050784:Proto-Oncogene Protein c-ets-1 / Q000502:physiology*; D015533:Transcriptional Activation; D015854:Up-Regulation; D050807:ets-Domain Protein Elk-1 / Q000502:physiology*; D000099162:Endothelial PAS Domain-Containing Protein 1
chemical_list: D000071916:AC133 Antigen; D015703:Antigens, CD; D051792:Basic Helix-Loop-Helix Proteins; D006023:Glycoproteins; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D010455:Peptides; D050784:Proto-Oncogene Protein c-ets-1; D050807:ets-Domain Protein Elk-1; D000099162:Endothelial PAS Domain-Containing Protein 1; C494112:ELK1 protein, human; C494041:ETS1 protein, human; C497442:HIF1A protein, human; C000606023:PROM1 protein, human