Sp1 and AP-1 Regulate Expression of the Human Gene VIL2 in Esophageal Carcinoma Cells

Abstract

Ezrin, encoded by VIL2, is a membrane-cytoskeletal linker protein that has been suggested to be involved in tumorigenesis. Ezrin expression in esophageal squamous cell carcinoma (ESCC) was described recently, but its clinical significance and the molecular mechanism underlying its regulated expression remain unclear. Thus, we retrospectively evaluated ezrin expression by immunohistochemistry in a tissue microarray representing 193 ESCCs. Ezrin overexpression in 90 of 193 tumors (46.6%) was associated with poor survival (p ‫؍‬ 0.048). We then explored the mechanism by which ezrin expression is controlled in ESCC by assessing the transcriptional regulatory regions of human VIL2 by fusing deletions or site-directed mutants of the 5-flanking region of the gene to a luciferase reporter. We found that the region ؊87/؊32 containing consensus Sp1 (؊75/؊69) and AP-1 (؊64/؊58) binding sites is crucial for VIL2 promoter activity in esophageal carcinoma cells

Regulation of Xylosyltransferase I Gene Expression by Interleukin 1β in Human Primary Chondrocyte Cells

“…Analysis of sequence directly upstream of the transcriptional initiation site revealed that the human XT-I promoter is a GC-rich TATAless promoter containing proximal Sp1-binding sites as reported previously (24). Similar promoters are found in many mammalian genes such as GlcAT-I (24), VIL2 (33), and UDPglucose dehydrogenase genes (34). Deletion analysis demonstrated that the Ϫ450 bp of the immediate 5Ј-flank is not sufficient to confer promoter activity in chondrocyte cells.…”

SILAC-based quantitative proteomic approach to identify potential biomarkers from the esophageal squamous cell carcinoma secretome

“…43 In earlier studies of ESCC, the expression of EZR protein was studied by western blotting, IHC labeling or RT-PCR. [44][45][46] In the current study, EZR was 2.5-fold upregulated in the ESCC secretome. Zeng et al studied and reported an association of EZR overexpression with poor survival in ESCC using IHC labeling.…”

Potential transcriptional regulatory regions exist upstream of the human ezrin gene promoter in esophageal carcinoma cells

“…We have also demonstrated that ezrin is overexpressed in a malignantly transformed esophageal epithelial cell line compared to an immortalized cell line [17]. Our recent studies on esophageal squamous cell carcinoma (ESCC) samples have shown that ezrin tends to translocate from the plasma membrane to the cytoplasm in the progression from normal epithelium to invasive carcinoma of the esophagus [18], and ezrin overexpression in ESCCs is associated with poor survival [19]. Moreover, both in vivo and in vitro experiments suggest that ezrin may directly affect tumor formation and tumor invasiveness [20].…”

“…These data suggest that ezrin levels are controlled at the transcriptional level. Our recent study on ezrin regulation demonstrated that the cooperativity of Sp1 and AP-1 (c-Jun/ c-Fos heterodimer) regulated VIL2 promoter activity and ezrin expression, and that mitogen-activated protein kinase kinase (MEK1/2) and extracellular signal-regulated kinase (ERK1/2) were upstream kinases that controlled human VIL2 transcriptional activation in ESCC cells [19]. There are relationships between ezrin expression and transcriptional activation of the VIL2 promoter in esophageal carcinoma cells.…”