Histone modifications affect differential regulation of TGFβ- induced NADPH oxidase 4 (NOX4) by wild-type and mutant p53

Abstract

Previously, we showed wild-type (WT) and mutant (mut) p53 differentially regulate reactive oxygen species (ROS) generation by NADPH oxidase-4 (NOX4): p53-WT suppresses TGFβ-induced NOX4, ROS and cell migration, whereas tumor-associated mut-p53 proteins enhance NOX4 expression and cell migration. Here, we extended our findings on the effects of p53 on NOX4 in several tumors and examined the basis of NOX4 transcriptional regulation by p53 and SMAD3. Statistical analysis of expression data from primary tumors available from The Cancer Genome Atlas (TCGA) detected correlations between mut-p53 and increased NOX4 expression. Furthermore, by altering p53 levels in cell culture models we showed several common tumor-associated mutant forms support TGFβ/SMAD3-dependent NOX4 expression. Deletion analysis revealed two critical SMAD3 binding elements (SBE) required for mut-p53-dependent NOX4 induction, whereas p53-WT caused dose-dependent suppression of NOX4 transcription. ChIP analysis revealed SMAD3 and p53-WT or mut-p53 associate with SBEs and p53 response elements in a TGFβ-dependent manner. Interestingly, the repressive effects of p53-WT on NOX4 were relieved by mutation of its transactivation domain or histone deacetylase (HDAC) inhibitor treatment. Overexpression of p300, a transcriptional co-regulator and histone acetyltransferase (HAT), enhanced p53-mediated NOX4 induction, whereas HAT-inactive p300 reduced NOX4 expression. Mut-p53 augmented TGFβ-stimulated histone acetylation within the NOX4 promoter. Finally, wound assays demonstrated NOX4 and p300 promote TGFβ/mut-p53-mediated cell migration. Our studies provide new insight into TGFβ/SMAD3 and mut-p53-mediated NOX4 induction involving epigenetic control of NOX4 in tumor cell migration, suggesting NOX4 is a potential therapeutic target to combat tumor progression and metastasis.

Brd4-p300 inhibition downregulates Nox4 and accelerates lung fibrosis resolution in aged mice

“…BET inhibition blocks the enrichment of transcriptional components (H4K16ac, Brd4, and p300) associated with the Nox4 promoter. Previously, we demonstrated that Nox4 transcription is associated with an active histone mark, H4K16ac (10), whereas inactivated p300 has been reported to reduce Nox4 expression in cancer cells (33). We examined whether decreased Nox4 gene expression by the BET inhibitor, OTX015, was due to the reduction of these transcriptional components at the Nox4 promoter.…”

The Chromatin Remodeler Brg1 Integrates ROS Production and Endothelial-Mesenchymal Transition to Promote Liver Fibrosis in Mice

“…We report here that Brg1 may rely on its interaction with the histone acetyltransferase p300 to activate NOX4 transcription and ROS production. Leto and colleagues have previously shown that mutant p53 drives NOX4 transcription in a range of different cancer cells via recruiting p300 to acetylate histone H4K8 surrounding the NOX4 promoter (Boudreau et al, 2017). Sanders et al (2015) and Liu et al (2019) have previously reported that up-regulation of NOX4 transcription is accompanied by accumulation of acetylated H4K16, mediated by the acetyltransferase hMOF/MYST1, on the NOX4 promoter in lung fibroblast cells and in hepatocytes, respectively.…”

Immune Cell Induced Migration of Osteoprogenitor Cells Is Mediated by TGF-β Dependent Upregulation of NOX4 and Activation of Focal Adhesion Kinase

“…So far, cell migration was often investigated in cancerous cell lines, e.g., lung and breast epithelial (cancer) cells. In these cells, this phenomenon was reported to be dependent on p53 status [ 24 ], which can be influenced by histone modifications [ 25 ]. However, this might be peculiar for cancer cells.…”

“…In migrating vascular smooth muscle cells, induction of NOX4 and ROS is associated with an activation of focal adhesion kinase (FAK) [ 23 ]. In migrating lung and breast epithelial cells, this phenomenon was reported to be dependent on p53 status [ 24 ], which in turn was tightly regulated by histone modifications [ 25 ]. These data indicate that NOX4 may be a key regulator of cell migration.…”