Promoter demethylation mediates the expression of ZNF645, a novel cancer/testis gene

Abstract

Cancer/testis (CT) antigens exhibit highly tissue-restricted expression and are considered promising targets for cancer vaccines. Here we identified a novel CT gene ZNF645 which restrictively expresses in normal human testes and lung cancer patients (68.3%). To investigate the promoter methylation status of ZNF645, we carried out bisulfite genomic sequencing and found that the CpG island in its promoter was heavily methylated in normal lung tissues without the expression of ZNF645, whereas there was high demethylation in normal human testes and lung carcinoma tissues with its expression. Also ZNF645 could be remarkably activated in A549 and HEK293T cells treated by DNA demethylation agent 5'-aza-2'-deoxycytidine. And the dual luciferase assay revealed that the promoter activity of the ZNF645 was inhibited by methylation of the CpG island region. Therefore, we proposed that ZNF645 is a CT gene and activated in human testis and lung cancers by demethylation of its promoter region. [BMB reports 2010; 43(6): 400-406]

Identification and characterization of methylation-dependent/independent DNA regulatory elements in the human SLC9B1 gene

“…While it is recognized that 5-azaC will result in global DNA demethylation, these results, when combined with the methylation dependence of P1 in our promoter assays, leave open the possibility that DNA methylation of P1 in somatic tissues prevents SLC9B1 gene expression and hypomethylation in the testis restricts its expression to this tissue. That methylation of the SLC9B1 P1 could repress transcription is not surprising as repression of transcription from methylated CpG island promoters has been previously documented for testis-specific genes (Deaton A and Bird A., 2011; Yu C et al, 2013; Bai G et al, 2010). …”

“…The activity of the promoterless pGL3-Basic vector is unaffected when subjected to this treatment (data not shown). Furthermore, the pGL3 basic vector has been previously used to study the effect of in vitro methylation on promoter activity (Bai G et al, 2010; Kabekkodu S P et al, 2014). The in vitro methylated and mock methylated pGL3-promoter1C1 constructs were transiently transfected in HEK 293 and GC-1spg cells and luciferase activity was assayed 48 hr later.…”

“…Methylation of the CpGs in the proximal promoter is responsible for silencing of the ALF gene in somatic cells (Xie W S et al, 2002). The expression of the cancer/testis (CT) gene, ZNF645 , is also regulated by DNA methylation - methylation of the promoter region being correlated with silencing of ZNF645 gene expression in somatic tissue (Bai G et al, 2010). More recently, the human RHOX gene cluster was shown to be regulated by DNA methylation.…”

Demethylation of CpG islands in the 5' upstream regions mediates the expression of the human testis-specific gene MAGEB16 and its mouse homolog Mageb16

“…To confirm that the MAGEB16 gene encodes a CT antigen, future investigations should be undertaken to screen its expression and to test the sero-reactivity of MAGEB16 antibodies in cancer patients, in a manner similar to previous reports (13,14). The mouse Mageb16 gene was also uniquely expressed in the testis, and the mRNA level in the testis increased through development and reached the highest level of expression at day 18 postnatal.…”

Epigenetic regulation of the X-chromosomal macrosatellite repeat encoding for the cancer/testis gene CT47

“…18,27,28 Using bisulfite sequencing, we measured the level of DNA methylation in the promoter region of CT47, from 275 bp upstream from the first exon, in LCLs and SCLCs (Figure 4e), as well as in hESCs and hEBs (Supplementary Figure S3). The promoter region of CT47 contains seven CpGs.…”