BCL2 promotor methylation and miR-15a/16-1 upregulation is associated with sanguinarine-induced apoptotic death in rat HSC-T6 cells

Previous studies show that several pathways are involved in sanguinarine-induced apoptotic cell death,including akt downregulation,inhibition of nf-kb activation,mediation of ros production,downregulation of anti-apoptosis proteins xiap and ciap-1,upregulation of bax,and downregulation of bcl2. in this study,we found out that the quenching of ros generation by n-acetyl-l-cysteine (nac),a scavenger of ros,reversed sanguinarine-induced apoptosis effects,also we found out that sanguinarine-induced rat hepatic stellate t6 cells (hsc-t6 cells) apoptosis was correlated with the generation of increased ros,which was followed by the activation of caspase-8 (-3,-6,and -9),and the decreasing in the miltochondrial membrane potential (mmp) and the down-regulation of anti-apoptotic protein bcl-2. it is not clear whether bcl2's downregulation relates to its promoter methylation and mir-15a/16-1 expression which can bind to bcl2 3′-utr (un-translation reagon). we showed that sanguinarine-induced down regulation of bcl2 was associated with the increased methylation rate of bcl2 promotor district and the increased expression of mir-15a/16-1. hsc-t6 cells treatment with 5-aza-2'-deoxycytidine (5′-aza-cdr) impeded sanguinarine-induced bcl2 promotor district methylation and recovered bcl2's expression. over expression of bcl2 using pegfp-n1 vector decreased sanguinarine-induced hsc-t6 cells apoptotic death significantly but not completely. these observations clearly showed that bcl2 down regulation was associated with its promoter methylation and mir-15a/16-1 upregulation in sanguinarine-induced rat hsc-t6 cells. © 2014 japanese pharmacological society.