Involvement of aberrant DNA methylation in the deregulated expression of EHF, LPAR1, MPZL3, and POPDC2 genes in equine sarcoids

Sarcoids are the most common dermatological tumor of equids worldwide. These fibroblastic tumors rarely regress, more often they remain and can be locally invasive. To explore the functional importance of DNA methylation during the BPV-dependent neoplasia of equine dermal tissues, this study assessed a methylation level of CpG islands (CGIs) in the promoter region of LPAR1, MPZL3, and POPDC2 genes, and within the gene body of the EHF gene, which were found to be differentially expressed in sarcoid samples in a previous study and harbored the differentially methylated sites (DMSs) in their sequences. The results of bisulfite sequencing PCR (BSP) showed a decrease in the methylation levels of CGIs of LPAR1 and EHF genes and an increase in the case of POPDC2. The obtained data did not reveal any changes in the level of DNA methylation in the analyzed promoter region of the MPZL3 gene between the tumor and healthy tissues. Our observations confirm the presence of CpG methylation alternations in the equine sarcoid and provide new insight into a better understanding of the epigenetic regulation of this tumor development.