title: Sp1 transcriptionally regulates BRK1 expression in non-small cell lung cancer cells.
abstract: Following a previous study reporting that BRK1 is upregulated in non-small cell lung cancer (NSCLC), the present study sought to clarify the role of specificity protein 1 (Sp1) in the transcriptional regulation of the BRK1 gene. Therefore, a construct, named F8, consisting of the -1341 to -1 nt sequence upstream of the start codon of the BRK1 gene inserted into pGL4.26 was made. A series of truncated fragments was then constructed based on F8. Segment S831, which contained the -84 to -1 nt region, displayed the highest transcriptional activity in the A549, H1299 and H520 NSCLC cell lines. Bioinformatic analysis showed a potential Sp1-binding element at -73 to -64 nt, and a mutation in this region suppressed the transcriptional activity of S831. Then the RNAi assays of Sp1 and its coworkers Sp3 and Sp4 were performed, and suppression of Sp1 by siRNA inhibited the mRNA expression of BRK1. Both an electrophoretic mobility shift assay (EMSA) and a chromatin immunoprecipitation (ChIP) assay demonstrated that Sp1 bound to the promoter area of the BRK1 gene. Our data identified a functional and positive Sp1 regulatory element from -73 to -64 nt in the BRK1 promoter, which may likely explain the overexpression of BRK1 in NSCLC.
authors.affiliation: State Key Laboratory of Molecular Oncology, Cancer Institute (Hospital), Peking Union Medical College & Chinese Academy of Medical Sciences, Beijing 100021, China.
authors.forename: Meng
authors.initials: M
authors.lastname: Li
authors.affiliation: State Key Laboratory of Molecular Oncology, Cancer Institute (Hospital), Peking Union Medical College & Chinese Academy of Medical Sciences, Beijing 100021, China.
authors.forename: Bing
authors.initials: B
authors.lastname: Ling
authors.affiliation: State Key Laboratory of Molecular Oncology, Cancer Institute (Hospital), Peking Union Medical College & Chinese Academy of Medical Sciences, Beijing 100021, China.
authors.forename: Ting
authors.initials: T
authors.lastname: Xiao
authors.affiliation: State Key Laboratory of Molecular Oncology, Cancer Institute (Hospital), Peking Union Medical College & Chinese Academy of Medical Sciences, Beijing 100021, China.
authors.forename: Jinjing
authors.initials: J
authors.lastname: Tan
authors.affiliation: State Key Laboratory of Molecular Oncology, Cancer Institute (Hospital), Peking Union Medical College & Chinese Academy of Medical Sciences, Beijing 100021, China.
authors.forename: Ning
authors.initials: N
authors.lastname: An
authors.affiliation: State Key Laboratory of Molecular Oncology, Cancer Institute (Hospital), Peking Union Medical College & Chinese Academy of Medical Sciences, Beijing 100021, China.
authors.forename: Naijun
authors.initials: N
authors.lastname: Han
authors.affiliation: State Key Laboratory of Molecular Oncology, Cancer Institute (Hospital), Peking Union Medical College & Chinese Academy of Medical Sciences, Beijing 100021, China.
authors.forename: Suping
authors.initials: S
authors.lastname: Guo
authors.affiliation: State Key Laboratory of Molecular Oncology, Cancer Institute (Hospital), Peking Union Medical College & Chinese Academy of Medical Sciences, Beijing 100021, China.
authors.forename: Shujun
authors.initials: S
authors.lastname: Cheng
authors.affiliation: State Key Laboratory of Molecular Oncology, Cancer Institute (Hospital), Peking Union Medical College & Chinese Academy of Medical Sciences, Beijing 100021, China. Electronic address: zhangkt@cicams.ac.cn.
authors.forename: Kaitai
authors.initials: K
authors.lastname: Zhang
mesh_terms: D001665:Binding Sites / Q000235:genetics; D002289:Carcinoma, Non-Small-Cell Lung / Q000235:genetics* / Q000473:pathology; D045744:Cell Line, Tumor; D047369:Chromatin Immunoprecipitation; D018387:Codon, Initiator; D003598:Cytoskeletal Proteins / Q000235:genetics* / Q000378:metabolism; D024202:Electrophoretic Mobility Shift Assay; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008156:Luciferases / Q000235:genetics; D008175:Lung Neoplasms / Q000235:genetics* / Q000473:pathology; D011401:Promoter Regions, Genetic; D012045:Regulatory Sequences, Nucleic Acid; D016329:Sp1 Transcription Factor / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic
chemical_list: C519848:BRK1 protein, human; D018387:Codon, Initiator; D003598:Cytoskeletal Proteins; D016329:Sp1 Transcription Factor; D008156:Luciferases
keywords: BRK1; NSCLC; Promoter; Sp1; Transcriptional regulation