Together , they activate multiple signal transduction pathways including oxidant stress , tyrosine kinase s , Protein kinase C , and MAPK s leading to activation of transcription factors such as NF-κB , and dysregulation of epigenetic mechanisms including HKme , histone lysine acetylation , and DNA methylation via the action of corresponding methyltransferases , demethylases , acetylases , and deacetylases .