O-GlcNAc regulates MTA1 transcriptional activity during breast cancer cells genotoxic adaptation

Chromatin modifier metastatic tumor protein 1 (MTA1), closely correlated with the development and progression in breast cancer, has a fantastic role in multiple cellular processes, including gene expression and cell homeostasis. Although MTA1 is a stress-responsive gene, its role in genotoxic adaptation remains unexplored. Here, we demonstrate that O-GlcNAc modification promotes MTA1 to interact with chromatin and regulates target gene expression, contributing to breast cancer cell genotoxic adaptation. MTA1 is modified with O-GlcNAc residues at serine 237/241/246 in adriamycin adaptive breast cancer cells and that modification improves the genome-wide interactions of MTA1 with gene promotor regions by enhancing its association with nucleosome remodeling and histone deacetylation (NuRD) complex. Further, O-GlcNAc-modulated MTA1 chromatin-binding influences the specific transcriptional regulation of genes involved in the adaptation of breast cancer cells to genotoxic stress. We performed chromatin immunoprecipitation followed by sequencing (ChIP-seq) using anti-HA magnetic beads in HA-MTA1-WT or HA-MTA1-3A stably expressed MCF-7 cells. Next-generation sequencing libraries were generated and amplified for 15 cycles with BGISEQ kit. 100-300 bp DNA fragments were gel-purified and sequenced with BGISEQ-500 (BGI). Two biological replicates of the ChIP-seq were performed. We also analyzed gene expression in MTA1-WT and MTA1-3A expressed cells by RNA-seq. MTA1 ChIP-seq was performed in HA-MTA1-WT and HA-MTA1-3A expressed MCF-7 cells using anti-HA magnetic beads. Gene expression profiling of HA-MTA1-WT and HA-MTA1-3A expressed MCF-7 cells were performed by RNA-seq.