The tumor suppressor phosphatase and tensin homolog protein (PTEN) is negatively regulated by NF-κb p50 homodimers and involves histone 3 methylation/deacetylation in UROtsa cells chronically exposed to monomethylarsonous acid.

•PTEN gene expression is modulated by NF-κβ in UROtsa cells exposed in vitro to MMAIII.•NF-κβ p50 homodimers binding to PTEN promoter is associated with decreased PTEN expression.•Increased H3 K9 and K27 trimethylation and decreased H3 total acetylation occurs at the NF-κβ binding sequence at PTEN promoter.