Effect of CCAAT/enhancer-binding protein homologeus protein on differentiation in Tan II A induced acute promyelocytic leukemia cells

Objective To investigate the effect of CCAAT/enhancer-binding protein homologeus protein (CHOP) in Tan Ⅱ A treated acute promyelocytic leukemia (APL) cells.Methods APL cell differentiation was monitored by morphology and membrane differentiation antigens; expression of CHOP was inhibited by siCHOP; mRNA and protein expression of CHOP in Tan Ⅱ A-intervened APL cells were examined by RT-PCR and Western blot.Results Expression of CHOP was increased in Tan Ⅱ A induced differentiated APL cells (proteins levels 1.933±0.987 vs 0.537±0.110,F =114.852,P ＜ 0.01,mNRA levels 1.587±0.815 vs 0.713±0.090,F =52.256,P ＜ 0.01),combination of CHOP gene silencing with Tan Ⅱ A treatment induced strong APL cell differentiation [(50.767±1.241) ％ vs (16.167±2.122) ％,F =989.431,P ＜ 0.05] and apoptosis [(89.233±5.581) ％ vs (27.433±2.957) ％,F =308.961,P ＜ 0.05].Conclusion CHOP acts as a negative regulator in Tan Ⅱ A induced differentiation.Inhibition of CHOP may be a promising therapeutic strategy. Key words: Tan Ⅱ A;  CHOP;  Leukemia, promyelocytic, acute;  Differentiation;  Apoptosis