SETD1A to induce epithelial-mesenchymal transition to promote invasion and metastasis through epigenetic reprogramming of snail in gastric cancer.

Abstract

241 Background: Aberrant epigenetic modification induces oncogenes expression and promotes cancer development. The histone lysine methyltransferase SETD1A, which specifically methylates H3K4, is involved in tumor growth and metastasis, and its ectopic expression has been detected in aggressive malignancies. Our previous study had reported that SETD1A promoted gastric cancer (GC) proliferation and tumorigenesis. However, the function and molecular mechanisms of SETD1A in GC metastasis remain to be elucidated. Methods: Transwell migration and invasion assay were performed to determine GC cell migration and invasion. Lung metastasis assay was used to detect GC cell metastasis. Western Blot and Real-time qPCR were performed to measure the protein and mRNA levels, respectively. ChIP assay was performed to investigate the methylation of H3K4. The correlation between SETD1A and EMT associated key genes in GC were performed by bioinformatic analysis. Results: In this study, we found that overexpression of SETD1A promotes GC migration and invasion, whereas knockdown of SETD1A suppressed GC migration, invasion and metastasis. Furthermore, knockdown of SETD1A suppressed GC epithelial-mesenchymal transition (EMT) by increasing the expression of epithelial marker E-cadherin, and decreasing the expression of mesenchymal markers, including N-cadherin, Fibronectin and Vimentin. Mechanistically, knockdown of SETD1A reduced the EMT key transcriptional factors snail. SETD1A was recruited to the promoter of snail, where SETD1A could methylate H3K4. However, knockdown of SETD1A decreased the methylation of H3K4 on snail promoter. Rescue of snail restored SETD1A knockdown-induced GC migration and invasion inhibition. In addition, linear correlation between SETD1A and several key EMT genes, including E-cadherin, Fibronectin and snail, in GC specimens obtained from TCGA dataset. Conclusions: In summary, our data reveals that SETD1A mediated EMT process and induced metastasis through epigenetic reprogramming of snail.