title: Evidence that Sp1 positively and Sp3 negatively regulate and androgen does not directly regulate functional tumor suppressor 15-lipoxygenase 2 (15-LOX2) gene expression in normal human prostate epithelial cells.
abstract: In this project, we studied the gene regulation of 15-lipoxygenase 2 (15-LOX2), the most abundant arachidonate-metabolizing LOX in adult human prostate and a negative cell-cycle regulator in normal human prostate (NHP) epithelial cells. Through detailed in silico promoter examination and promoter deletion and activity analysis, we found that several Sp1 sites (i.e., three GC boxes and one CACCC box) in the proximal promoter region play a critical role in regulating 15-LOX2 expression in NHP cells. Several pieces of evidence further suggest that the Sp1 and Sp3 proteins play a physiologically important role in positively and negatively regulating the 15-LOX2 gene expression, respectively. First, mutations in the GC boxes affected the 15-LOX2 promoter activity. Second, both Sp1 and Sp3 proteins were detected in the protein complexes that bound the GC boxes revealed by electrophoretic mobility shift assay. Third, importantly, inhibition of Sp1 activity or overexpression of Sp3 both inhibited the endogenous 15-LOX2 mRNA expression. Since 15-LOX2 is normally expressed in the prostate luminal epithelial cells, we subsequently explored whether androgen/androgen receptor may directly regulate its gene expression. The results indicate that androgen does not directly regulate 15-LOX2 gene expression. Together, these observations provide insight on how 15-LOX2 gene expression may be regulated in NHP cells.
authors.affiliation: Department of Carcinogenesis, Science Park-Research Division, The University of Texas MD Anderson Cancer Center, 1808 Park Rd. 1C, Smithville, TX 78957, USA.
authors.forename: Shaohua
authors.initials: S
authors.lastname: Tang
authors.forename: Bobby
authors.initials: B
authors.lastname: Bhatia
authors.forename: Jianjun
authors.initials: J
authors.lastname: Zhou
authors.forename: Carlos J
authors.initials: CJ
authors.lastname: Maldonado
authors.forename: Dhyan
authors.initials: D
authors.lastname: Chandra
authors.forename: Eunjung
authors.initials: E
authors.lastname: Kim
authors.forename: Susan M
authors.initials: SM
authors.lastname: Fischer
authors.forename: Andrew P
authors.initials: AP
authors.lastname: Butler
authors.forename: Scott L
authors.initials: SL
authors.lastname: Friedman
authors.forename: Dean G
authors.initials: DG
authors.lastname: Tang
mesh_terms: D000728:Androgens / Q000502:physiology*; D001093:Arachidonate 15-Lipoxygenase / Q000235:genetics*; D001483:Base Sequence; D004268:DNA-Binding Proteins / Q000502:physiology*; D004847:Epithelial Cells / Q000201:enzymology; D015971:Gene Expression Regulation, Enzymologic; D006801:Humans; D008297:Male; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D011467:Prostate / Q000201:enzymology*; D016329:Sp1 Transcription Factor / Q000502:physiology*; D051705:Sp3 Transcription Factor; D014157:Transcription Factors / Q000502:physiology*
chemical_list: D000728:Androgens; D004268:DNA-Binding Proteins; C497121:SP3 protein, human; D016329:Sp1 Transcription Factor; D014157:Transcription Factors; D051705:Sp3 Transcription Factor; C458528:ALOX15B protein, human; D001093:Arachidonate 15-Lipoxygenase