title: Aryl Hydrocarbon Receptor Activates NDRG1 Transcription under Hypoxia in Breast Cancer Cells.
abstract: Hypoxia has been intensively investigated over the past several decades based on the observations that hypoxic tumors are more resistant to therapy and have a worse prognosis. Previously, we reported that N-myc downstream-regulated gene 1 (NDRG1) is strongly up-regulated under hypoxia and may play an important role in tumor adaptation to fluctuating oxygen concentrations. However, the regulatory mechanism of NDRG1 under hypoxia remains elusive. Therefore, the purpose of this study was to identify the transcription factors that regulate NDRG1 and to investigate the functional roles of NDRG1 in hypoxia. We showed that binding sites of aryl hydrocarbon receptor (AHR) were predicted in the NDRG1 promoter. Nuclear AHR was up-regulated in the presence of cobalt and hypoxia. AHR translocated to nuclei and bound between base pairs -412 and -388 of the NDRG1 promoter in hypoxia. Moreover, hypoxia-mimetic induction of NDRG1 was attenuated by knockdown of AHR expression. Also, overexpression of AHR facilitated cell proliferation and migration via up-regulation of NDRG1. These results showed for the first time that AHR positively regulates NDRG1 transcription through an AHR binding site by way of hypoxia-mimetic signaling, which may lead to development of a specific therapeutic regimen to prevent tumor malignancy under hypoxia.
authors: Graduate Institute of Physiology, National Taiwan University, Taipei, Taiwan.
authors: En-Yu
authors: EY
authors: Li
authors: Graduate Institute of Physiology, National Taiwan University, Taipei, Taiwan.
authors: Wei-Yung
authors: WY
authors: Huang
authors: Graduate Institute of Physiology, National Taiwan University, Taipei, Taiwan.
authors: Ya-Chu
authors: YC
authors: Chang
authors: Institute of Biotechnology, National Taiwan University, Taipei, Taiwan.|Bioinformatics and Biostatistics Core, Center of Genomic Medicine, National Taiwan University, Taipei, Taiwan.
authors: Mong-Hsun
authors: MH
authors: Tsai
authors: Bioinformatics and Biostatistics Core, Center of Genomic Medicine, National Taiwan University, Taipei, Taiwan.|Graduate Institute of Biomedical Electronics and Bioinformatics, National Taiwan University, Taipei, Taiwan.
authors: Eric Y
authors: EY
authors: Chuang
authors: Graduate Institute of Clinical Medical Science, China Medical University, Taichung, Taiwan.
authors: Qian-Yu
authors: QY
authors: Kuok
authors: Graduate Institute of Clinical Medical Science, China Medical University, Taichung, Taiwan.
authors: Shih-Ting
authors: ST
authors: Bai
authors: Graduate Institute of Physiology, National Taiwan University, Taipei, Taiwan.
authors: Lo-Yun
authors: LY
authors: Chao
authors: Graduate Institute of Clinical Medical Science, China Medical University, Taichung, Taiwan.|Center for Molecular Medicine, China Medical University Hospital, Taichung, Taiwan.
authors: Yuh-Pyng
authors: YP
authors: Sher
authors: Graduate Institute of Physiology, National Taiwan University, Taipei, Taiwan.|Bioinformatics and Biostatistics Core, Center of Genomic Medicine, National Taiwan University, Taipei, Taiwan.
authors: Liang-Chuan
authors: LC
authors: Lai
mesh_terms: D001665:Binding Sites; D001943:Breast Neoplasms / Q000503:physiopathology*; D018797:Cell Cycle Proteins / Q000096:biosynthesis* / Q000235:genetics; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D005786:Gene Expression Regulation; D006801:Humans; D000860:Hypoxia; D047908:Intracellular Signaling Peptides and Proteins / Q000096:biosynthesis* / Q000235:genetics; D011401:Promoter Regions, Genetic; D018336:Receptors, Aryl Hydrocarbon / Q000378:metabolism*; D014158:Transcription, Genetic; D000099259:N-myc Downstream-Regulated Gene 1 Protein
chemical_list: D018797:Cell Cycle Proteins; D047908:Intracellular Signaling Peptides and Proteins; D018336:Receptors, Aryl Hydrocarbon; D000099259:N-myc Downstream-Regulated Gene 1 Protein