Identification of an invasion and tumor‐suppressing gene, Endoglin (ENG), silenced by both epigenetic inactivation and allelic loss in esophageal squamous cell carcinoma

Abstract

Endoglin (ENG) has been identified as a candidate tumor-suppressor gene in esophageal squamous cell carcinoma (ESCC). Earlier microcell-mediated chromosome transfer (MMCT) studies of chromosome 9 in ESCC narrowed down a tumor-suppressive critical region to 9q33-34. ENG maps to 9q34-qter and encodes a transformation growth factor beta (TGFb) superfamily auxiliary receptor. This study aims to identify the potential role for ENG in ESCC development. Significant downregulation of ENG was detected at frequencies of 87.5% in 16 ESCC cell lines, 39.1% directly in 23 ESCC tumor specimens from Hong Kong, and 33.4% in 18 ESCC tumor specimens from the high-risk ESCC region of Henan, China. By methylation-specific PCR, methylated sequences were detected in an ESCC cell line panel and in clinical specimens. Following demethylation treatment in 9 ESCC cell lines, ENG expression was obviously restored. Loss of heterozygosity (LOH) in a 4.7 Mb region on 9q32-q34, where ENG maps, was observed directly in ESCC tumor tissues. Both epigenetic methylation and allelic loss appear to contribute to ENG downregulation in tumor cells. In vitro and in vivo functional studies such as colony formation, Matrigel culture, invasion and tumorigenicity assays were performed. Colony formation efficiency was significantly reduced by overexpression of ENG. In addition, significantly smaller colonies of ENG stable transfectants were formed in Matrigel culture. Significant suppression of invasion efficiency and tumorigenicity were also observed, when comparing the ENG stable transfectants with the vector-alone transfectants. This study provides evidence supporting ENG, as a cell invasion and tumor-suppressing gene in ESCC.

Endoglin expression in breast tumor cells suppresses invasion and metastasis and correlates with improved clinical outcome

“…Further, we demonstrated by MSP analysis and bisulfite sequencing that endoglin expression in breast cancers and cancer cell lines is epigenetically regulated by gene methylation. This latter finding extends previous work in which MSP analysis was used to demonstrate ENG CpG island methylation in esophageal cell lines and two esophageal tumors (Wong et al, 2008) and indicates that this mechanism of ENG gene regulation may be utilized in multiple cancer types. Of interest, reduced endoglin expression enhances malignant progression in a mouse model of skin carcinogenesis (Quintanilla et al, 2003); however, the mode of endoglin downregulation is by shedding of the extracellular domain (Perez-Gomez et al, 2007).…”

Prognostic significance of the preoperative serum levels of soluble form of endoglin in gastric cancer patients

“…In prostate cancer, endoglin was detected in epithelial cells of both prostatic intraepithelial neoplasia and malignant areas (4). Endoglin expression is down-regulated in both primary esophageal squamous cell carcinomas and cell lines, and overexpression of endoglin in esophageal squamous cell carcinomas cells led to reduced invasiveness and tumorigenicity (8). Endoglin expression in breast tumor cells suppresses the invasion and metastasis, and correlates with improved clinical outcome (9).…”

Molecular and immunohistochemical evidence for the origin of uterine leiomyosarcomas from associated leiomyoma and symplastic leiomyoma-like areas

“…21 Endoglin has been identified as a candidate tumor suppressor gene in esophageal squamous cell carcinoma. 22 PDGFB is a mitogenic factor for mesenchymal cells, 23 and its loss is difficult to explain in leiomyoma-like areas. Perhaps other tumor suppressor genes are located in the vicinity of PDGFB, which is at 22q13.1.…”