Downregulation of ID4 by promoter hypermethylation in gastric adenocarcinoma

Abstract

Promoter hypermethylation has become apparent as a common mechanism of gene silencing in cancer. Based on our published microarray expression data, we noticed a prominent downregulation of ID4 in gastric adenocarcinoma. The dense 5 0 CpG island covering the previously mapped upstream promoter of ID4 has prompted us to relate its downregulation to promoter hypermethylation. ID proteins are distinct members in the helix-loop-helix family of transcriptional regulators, which modulate various key developmental processes. Emerging data have suggested the involvement of ID genes in tumorigenesis. In this study using bisulfite genomic sequencing, we have found hypermethylation of ID4 promoter in most gastric cancer cell lines and 30% of primary tumors. This correlated with decreased level of ID4 expression. Restoration of ID4 expression in various gastric cancer cell lines was achieved by treatment with the DNA methyltransferase inhibitor 5-aza-2 0 -deoxycytidine, which at times required the synergistic action of the histone deacetylase inhibitor trichostatin A, but not with trichostatin A alone. Re-expression was accompanied by the corresponding ID4 promoter demethylation. Furthermore, we have found significant association of ID4 promoter methylation with hMLH1 promoter methylation (P ¼ 0.008) and microsatellite instability (P ¼ 0.006). Overall, our results have shown that transcriptional silencing of ID4 is related to the aberrant methylation of its promoter in gastric cancer. The significant association of ID4 and hMLH1 promoter hypermethylation suggested that ID4 may also be among the genes being targeted in the CpG island methylator phenotype tumorigenic pathway.

Induction of Lumen Formation in a Three-dimensional Model of Mammary Morphogenesis by Transcriptional Regulator ID4

“…As previously noted, the proximal promoter of the ID4 gene has a CpG island that is hypermethylated in gastric cancer (15). Using reduced representation bisulfite sequence analysis, we found hypermethylation of the ID4 promoter in vector control MCF7 cells and hypomethylation in CEACAM1-transfected MCF7 cells (Fig.…”

Inhibitor of DNA binding-4 promotes angiogenesis and growth of glioblastoma multiforme by elevating matrix GLA levels

“…ID family members including ID1, ID2, and ID3 have identified functions in tumor progression, including angiogenesis, invasion, and metastasis (Lyden et al, 1999;Benezra, 2001;Benezra et al, 2001;Folkman, 2002;Ruzinova and Benezra, 2003;, and in other circumstances ID1 and ID2 may function as tumor suppressors in rodents (Itahana et al, 2003;Sikder et al, 2003;Russell et al, 2004). The function of ID4 in tumorigenesis is similarly complex (Beger et al, 2001;Bellido et al, 2003;Chan et al, 2003;Shan et al, 2003;Umetani et al, 2004Umetani et al, , 2005 Jeon et al, 2008). ID4 seems to function as a tumor suppressor in a variety of cancers (Chan et al, 2003;Umetani et al, 2004Umetani et al, , 2005Yu et al, 2005) and is downregulated by promoter hypermethylation in several tumor types (Chan et al, 2003;Umetani et al, 2004Umetani et al, , 2005Yu et al, 2005).…”

“…The function of ID4 in tumorigenesis is similarly complex (Beger et al, 2001;Bellido et al, 2003;Chan et al, 2003;Shan et al, 2003;Umetani et al, 2004Umetani et al, , 2005 Jeon et al, 2008). ID4 seems to function as a tumor suppressor in a variety of cancers (Chan et al, 2003;Umetani et al, 2004Umetani et al, , 2005Yu et al, 2005) and is downregulated by promoter hypermethylation in several tumor types (Chan et al, 2003;Umetani et al, 2004Umetani et al, , 2005Yu et al, 2005). In sharp contrast, however, ID4 promotes some aspects of tumorigenesis in B-cell lineage ALL, glioblastoma, and sporadic breast and ovarian cancers (Beger et al, 2001;Bellido et al, 2003;Jeon et al, 2008), and its expression is heightened in bladder cancer because of gene amplification .…”

Promotormethylierung von ID4

“…In Karzinomen des Pankreas [15] und des Dickdarms [15,29] ist die Genexpression von ID1, ID2 und ID3 deutlich aufreguliert; folglich wurde diesen Genen primär ein onkogener Charakter zugeschrieben. ID4 hingegen scheint als Tumorsuppressor zu fungieren, da seine RNA-Expression in Prostatakarzinomen [1], humanen Leukämien [32], kolorektalen Karzinomen [25] und Adenokarzinomen des Magens [4] deutlich niedriger ist als in den entsprechenden Normalgeweben.…”

“…Für das humane Mammakarzinom wurde bereits die epigenetische Inaktivierung durch eine Hypermethylierung für BRCA1, 14-3-3σ, TIMP3, ESR1, PGR und CDH1 beschrieben [10]. Die Promotorregion von ID4 enthält ebenfalls CpG-Inseln, welche in Adenokarzinomen des Magens als hypermethyliert gefunden wurden und mit dem Verlust der ID4-Gen-Expression assoziiert sind [4]. Verschiedene Studien postulierten eine mögliche Korrelation zwischen ID4-Promotor-Methylierung und Tumorinitiation bzw.…”