miR-646/TET1 mediated demethylation of IRX1 promoter upregulates HIST2H2BE and promotes the progression of invasive ductal carcinoma.

Abstract Background This study aimed to explore role of miR-646 in breast IDC. Methods miR-646, TET1, IRX1, and HIST2H2BE expression was detected by RT-qPCR and/or Western blot analysis. The methylation status of IRX1 promoter region was evaluated by methylation specific PCR. ChIP assay was used to determine the enrichment of TET1 at IRX1 promoter region. Loss- and gain-of functions were performed to determine the roles of miR-646, TET1, IRX1, and HIST2H2BE in cell proliferation, migration, invasion, and apoptosis. The tumor growth, volume, weight, and apoptosis status were measured. Results miR-646 was upregulated while TET1 was downregulated in IDC tissues. miR-646 targeted TET1. Downregulated TET1 impairs demethylation of IRX1 promoter region resulting in reduced expression of IRX1, which subsequently leads to upregulation of HIST2H2BE in IDC. Consequently, elevated HIST2H2BE promotes progression of IDC. Conclusion Our study has demonstrated that miR-646 facilitates the tumorigenesis of IDC via regulating TET1/IRX1/HIST2H2BE axis.