Epigenetic Mechanisms Are Involved in the Oncogenic Properties of ZNF518B in Colorectal Cancer

Abstract

The ZNF518B gene, which is up-regulated in colorectal cancer, plays a role in cell dissemination and metastasis. It encodes a zinc-finger protein, which interacts with histone methyltransferases G9A and EZH2. The expression of the two major mRNA isoforms 1 (coding for the full protein) and 2 was quantified by RT-qPCR in a cohort of 66 patients. The effects of silencing ZNF518B on the transcriptome of DLD1 and HCT116 cells were analysed by Clariom-S assays and validated by RT-qPCR. The recruitment of methyltransferases and the presence of H3K27me3 were studied by chromatin immunoprecipitation (ChIP). The ratio (isoform 2)/(isoform 1) negatively correlated with the relapsing of disease. The study of the transcriptome of DLD1 and HCT116 cells revealed that many genes affected by silencing ZNF518B are related to cancer. After crossing these results with the list of genes affected by silencing the histone methyltransferases (retrieved in silico), five genes were selected. ChIP analysis revealed that the recruitment of EZH2 is ZNF518B-dependent in KAT2B, RGS4 and EFNA5; the level of H3K27me3 changes in accordance. G9A also binds RGS4 and PADI3 in a ZNF518B-dependent manner. The results highlight the importance of epigenetics in cancer and open a novel therapeutic possibility, as inhibition of histone methyltransferases may reverse the disease-linked histone marks.

Vitamin A Status Modulates Epithelial Mesenchymal Transition in the Lung: The Role of Furin

“…The ChIP procedure was performed as described previously [ 34 ]. In brief, lungs were surgically removed and fixed with 1% formaldehyde in PBS for 10 min.…”

Alternative Splicing, Epigenetic Modifications and Cancer: A Dangerous Triangle, or a Hopeful One?

“…Concerning the writers, the full-length histone methyltransferase EZH2, which catalyzes the introduction of the repressive mark H3K27me3, may favor EMT by inhibiting some suppressor genes, such as EFNA5, through a mechanism involving the recruitment of the enzyme by the zinc-finger factor ZNF518B [135]. The EZH2 gene possesses 20 exons; the inclusion of the alternative exon 14, driven by the overexpression of the upregulation of the splicing factor SF3B3, results in the increased proliferation of clear cell renal cell carcinoma.…”

Potential Therapeutics Targeting Upstream Regulators and Interactors of EHMT1/2

“…The ability to guide G9a to specific gene promoters is also observed with other zinc finger transcription factors. ZNF518B drives cell proliferation in CRC by silencing key tumor suppressors such as Peptidyl arginine deiminase 3 ( PADI3 ) and Regulator of G protein signaling ( RGS4 ) [ 117 ]. ZNF518B recruits and directs G9a to the promoters of PADI3 and RGS4 and represses their expression by catalyzing H3K9me2 [ 117 ].…”

“…ZNF518B drives cell proliferation in CRC by silencing key tumor suppressors such as Peptidyl arginine deiminase 3 ( PADI3 ) and Regulator of G protein signaling ( RGS4 ) [ 117 ]. ZNF518B recruits and directs G9a to the promoters of PADI3 and RGS4 and represses their expression by catalyzing H3K9me2 [ 117 ]. The knockdown of ZNF518B inhibits G9a occupancy on promoters, restoring the expression of the target genes to decrease cell proliferation and increase apoptosis [ 117 ].…”

“…ZNF518B recruits and directs G9a to the promoters of PADI3 and RGS4 and represses their expression by catalyzing H3K9me2 [ 117 ]. The knockdown of ZNF518B inhibits G9a occupancy on promoters, restoring the expression of the target genes to decrease cell proliferation and increase apoptosis [ 117 ].…”