Isolation and functional analysis of the human glioblastoma-specific promoter region of the human GD3 synthase (<italic>hST8Sia I</italic>) gene

Abstract

We identified the promoter region of the human GD3 synthase (hST8Sia I) gene to elucidate the mechanism underlying the regulation of hST8Sia I expression in human glioblastoma cells. The 5 0 -rapid amplification of cDNA end using mRNA prepared from U-87MG cells revealed the presence of transcription start site of hST8Sia I gene, and the 5 0 -terminal analysis of its product showed that transcription started from 648 nucleotides upstream of the translational initiation site. Functional analysis of the 5 0 -flanking region of the hST8Sia I gene by transient expression method revealed that the region from 2638 to 2498 is important for transcriptional activity of the hST8Sia I gene in U-87MG and T98G cells. This region lacks apparent TATA and CAAT boxes, but contains putative binding sites for transcription factors AREB6 and Elk-1. Sitedirected mutagenesis and transient transfection assays demonstrated that both AREB6 and Elk-1 elements in this region were required for the promoter activity in U-87MG and T98G cells. These results indicated that both AREB6 and Elk-1 might play an essential role in the transcriptional activity of hST8Sia I gene essential for GD3 synthesis in human glioblastoma cells.

Estradiol Represses the GD3 Synthase Gene ST8SIA1 Expression in Human Breast Cancer Cells by Preventing NFκB Binding to ST8SIA1 Promoter

“…Similar aberrant non-coding transcripts have recently been described in tumors and have been suggested to play functional roles in cancer progression and metastasis [34]. Interestingly, the core promoter we identified in breast cancer cells, between −923 and −565 upstream the initiation codon, overlaps with the core promoter found in melanoma (−833/−519) [24] and neuroblastoma (−1190/−690) [27] but not with the one found in glioblastoma (−1330/−1190) [26], suggesting a tissue-specific regulation of ST8SIA1. …”

“…ST8SIA1 is located on chromosome 12, in p12.1-p11.2 locus and consists in five coding exons spanning over 135 kbp [24]. Several reports have described the 5′-untranslated region (5′-UTR) of ST8SIA1 in melanoma [24], [25], glioblastoma [26] and neuroblastoma [27] cell lines, showing a unique transcript with transcription start sites (TSS) located 400 to 650 bp upstream the initiation codon on the first exon. In this study, we described the main ST8SIA1 transcript expressed in breast cancer tumors and cell lines and we characterized the core promoter of this gene.…”

Ganglioside GD2 identifies breast cancer stem cells and promotes tumorigenesis

“…Further analysis indicates that only GD3S and not GD2S mRNA expression was regulated during EMT. Moreover, Dae et al found that ZEB1, a known EMT-inducing transcription factor, directly binds to the GD3S promoter and induces transcription of GD3S in glioblastoma cells (32). These findings suggest that the EMT-inducing factors such as ZEB1 might bind to the GD3S promoter and upregulate its expression in CSCs as well as in EMT-derived cancer cells, which then generate GD3, due to the high basal expression of GD2S in these cells, which probably immediately converts to GD2 by ubiquitously expressed GD2S.…”

Glycosphingolipid metabolism in cell fate specification

“…During TGFβ-induced EMT, the mothers against decapentaplegic homolog 3 and 4 (Smad3-Smad4) complex represses B3GALT4 by binding to its promoter (Guo et al, 2015), whereas zinc finger E-box-binding homeobox 1 (Zeb1) (a transcriptional target of Smad3-Smad4) binds to and activates the promoters of both ST3GAL5 (Mathow et al, 2015) and ST8SIA1 (Dae et al, 2009). Importantly, exogenous provision of GA1 (one of the products of B3GALT4/GA1 synthase) inhibits TGFβ-induced EMT, which suggests that GSLs are both targets and regulators of the same signaling pathway (Guan et al, 2009;Guo et al, 2015) ( Fig.…”