Epithelial-mesenchymal transition (EMT), a cellular process that plays a key role in tumor initiation, invasion, metastasis, and therapeutic resistance in cancer, is regulated by tissue mechanics. Increased matrix stiffness associated with tumor progression promotes loss of epithelial cell polarity and adhesion properties, and cells adopt a mesenchymal phenotype characterized by increased motility and invasiveness. Despite its clinical significance, the precise mechanisms driving EMT in response to mechanical cues remain unclear. Among the potential regulatory factors, epigenetic modifications —heritable changes in gene expression without alterations to the DNA sequence—have emerged as key contributors. DNA methylation, particularly at CpG islands in gene promoter regions, is known to silence gene expression. DNA (cytosine-5)-methyltransferase 3A (DNMT3A), one of the key enzymes mediating this process, plays a critical role in establishing methylation patterns during development and in disease. Specifically, DNA methylation has been shown to modulate genes involved in cell adhesion, a hallmark of EMT. In this study, we investigated the impact of matrix mechanics on DNA methylation and gene expression during EMT. ound that DNA methylation and the expression levels of DNA methyltransferases are regulated by TGFβ1 and matrix stiffness. Cells cultured on a stiffer matrix that mimics the tumor microenvironment expressed increased levels of mesenchymal-associated proteins compared to those grown on a softer matrix. Furthermore, silencing DNMT3A led to a measurable decrease in mesenchymal marker expression, suggesting that modulation of DNA methylation may reverse EMT and potentially enhance therapeutic sensitivity among patients. These results indicate that tumor microenvironment regulation and epigenetic reprogramming could serve as a promising strategy to inhibit EMT and overcome drug resistance in cancer treatment.
