title: Up-regulation of glyceraldehyde-3-phosphate dehydrogenase gene expression by HIF-1 activity depending on Sp1 in hypoxic breast cancer cells.
abstract: Hypoxia up-regulates the expression of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) in a cell type-specific manner. It is unknown whether this occurs in breast cancer. Here, we report that hypoxia up-regulates the GAPDH gene expression through breast cancer-specific molecular mechanisms in MCF-7 cells. Mutation analysis identified a novel hypoxia response element (HRE), in addition to the HRE found previously in prostate cancer LNCaP cells. Knockdown and overexpression of hypoxia-inducible factor (HIF)-1α indicated that HIF-1 contributed to the up-regulation of GAPDH gene expression by hypoxia. Although chromatin immunoprecipitation (ChIP) and plasmid immunoprecipitation analyses revealed the presence of HIF-1α on the novel HRE in both hypoxic cell lines, a mutation in either the novel HRE or its 3'-flanking GC-box resulted in a reduction of hypoxia-increased GAPDH promoter activity only in MCF-7 cells. ChIP analysis showed that Sp1 bound to the GC-box in MCF-7 cells, but not in LNCaP cells, in normoxia and hypoxia. Knockdown of Sp1 reduced hypoxia-increased promoter activity and expression level of GAPDH in MCF-7 cells. These results indicate that in MCF-7 cells, the activation of HIF-1 on the novel HRE contributes to the breast cancer-specific hypoxic induction of GAPDH gene expression and absolutely depends on the presence of Sp1 on the GC-box.
authors.affiliation: Division of Applied Biological Chemistry, Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Sakai, Osaka 5998531, Japan.
authors.forename: Yasuki
authors.initials: Y
authors.lastname: Higashimura
authors.forename: Yoshito
authors.initials: Y
authors.lastname: Nakajima
authors.forename: Ryoichi
authors.initials: R
authors.lastname: Yamaji
authors.forename: Naoki
authors.initials: N
authors.lastname: Harada
authors.forename: Futoshi
authors.initials: F
authors.lastname: Shibasaki
authors.forename: Yoshihisa
authors.initials: Y
authors.lastname: Nakano
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Inui
mesh_terms: D001943:Breast Neoplasms / Q000235:genetics* / Q000378:metabolism; D015687:Cell Hypoxia; D045744:Cell Line, Tumor; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases / Q000235:genetics*; D006801:Humans; D051793:Hypoxia-Inducible Factor 1 / Q000378:metabolism*; D008297:Male; D011471:Prostatic Neoplasms / Q000235:genetics / Q000378:metabolism; D020218:Response Elements; D016329:Sp1 Transcription Factor / Q000378:metabolism*; D015533:Transcriptional Activation; D015854:Up-Regulation
chemical_list: D051793:Hypoxia-Inducible Factor 1; D016329:Sp1 Transcription Factor; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases