title: Sp1 upregulates the four and half lim 2 (FHL2) expression in gastrointestinal cancers through transcription regulation.
abstract: In this study, our purpose is to clarify the role of specificity protein 1 (Sp1) in transcription activation of the four and half lim 2 (FHL2). pLuc595 which contained -1163nt to -568nt upstream ATG starting codon displayed the highest while pLuc382 (-950nt to -568nt) displayed lowest transcription activities in GI cancer cells. Meanwhile, suppression of Sp1 by siRNA or chemical inhibitor, mithramycin A (MIT) inhibited the promoter activity and FHL2 expression. Bioinformatics analysis showed two putative Sp1 binding elements within pLuc595 while EMSA assay demonstrated that the wild type but not the mutated probe containing the distal element bound to the cell nuclear protein specifically. Mutation of the distal Sp1 binding sequence suppressed the transcription activity of pLuc595. In vivo study showed that both Sp1 and FHL2 were highly expressed by cancer cells but not the normal GI tissues with their expressions being positive correlated. These data identified a functional Sp1 positively regulatory element (-1058nt to -1049nt) within FHL2 promoter, and the positive correlation between Sp1 and FHL2 in expressing pattern and signal mechanism strongly suggested their synergized effect in carcinogenesis and progression of GI cancers.
authors.affiliation: Department of Gastroenterology, Nanfang Hospital, Southern Medical University, Guangzhou, China.
authors.forename: Zheng
authors.initials: Z
authors.lastname: Guo
authors.forename: Wenjing
authors.initials: W
authors.lastname: Zhang
authors.forename: Guosheng
authors.initials: G
authors.lastname: Xia
authors.forename: Lingyun
authors.initials: L
authors.lastname: Niu
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhang
authors.forename: Xinying
authors.initials: X
authors.lastname: Wang
authors.forename: Yali
authors.initials: Y
authors.lastname: Zhang
authors.forename: Bo
authors.initials: B
authors.lastname: Jiang
authors.forename: Jide
authors.initials: J
authors.lastname: Wang
mesh_terms: D001483:Base Sequence; D024202:Electrophoretic Mobility Shift Assay; D005770:Gastrointestinal Neoplasms / Q000235:genetics; D005786:Gene Expression Regulation; D006801:Humans; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D015533:Transcriptional Activation; D015854:Up-Regulation
chemical_list: D009687:Nuclear Proteins