Targeting redox-sensitive MBD2-NuRD condensate for tumor therapy [ATAC-seq]

Transcriptional silencing of hypermethylated tumor suppressor genes is a hallmark of tumorigenesis, though the underlying mechanism remains enigmatic. In this study, we find Methyl-CpG-binding domain protein 2 (MBD2) forms nuclear condensate in diverse cancer cells, where it assembles and navigates the chromatin remodeler NuRD complex to these gene loci for transcriptional suppression, thus fueling tumor growth. Disturbance of MBD2 condensate reduces the level of NuRD complex-specific proteins, destabilizes heterochromatin foci, facilitates chromatin relaxation, and consequently impedes tumor progression. We demonstrate that MBD2 condensate is redox sensitive mediated by Cys359. Prooxidative interventions disperse MBD2-NuRD condensate, thereby alleviating the transcriptional repression of tumor suppressor genes. Our findings illuminate a hitherto unappreciated function of MBD2 condensate in sustaining a repressive chromatin state essential for cancer cell proliferation and suggest an oxidative stress targeting approach for malignancies with excessive MBD2 condensate. Overall design: ATAC-seq for shCtrl, shMBD2, shMBD2+MBD2WT and shMBD2+MBD2KRR/E HeLa cells