[Down-regulation of AnnexinⅡExpression in NB4 Cells Induced by all-trans Retinoic Acid and Its Mechanisms].

Objective: To explore effect of all-trans retinoic acid(ATRA) on annexin Ⅱ expression in NB4 cells and to analyze the luciferase activity of annexinⅡ promoter in condition of ATRA-induced treatment.

Methods: NB4 cells were cultured in vitro, the transcriptional or translational expression levels of Annexin Ⅱ in NB4 cells treated with 1 µmol/L ATRA at different time points were detected by RT-PCR or Western blot respectively. Annexin Ⅱ-promoter was constructed, the recombinant plasmids pGL4.15 -Annexin Ⅱ -promoter were transfected into NB4 cells with electroporation, and after being treated with 1 µmol/L ATRA for 24 hours the luciferase acttivity of Annexin Ⅱ promoter was determined by luciferase activity assay.

Results: The transcriptional expression of Annexin Ⅱ was down-regulated after 48 h. The translation expression of Annexin Ⅱ was slowly weakened after 24 h, and it was seriously reduced after 48 h. Further, Luciferase activity of AnnexinⅡ promoter in NB4 cells treated with 1 µmol/L ATRA was down-regulated, and showed a decreased tendency at indicated time points.

Conclusion: All-trans retinoic acid can induce the down-regulation of AnnexinⅡ expression on the membrane of NB4 cells, and the activity of Annexin Ⅱpromoter is down-regulated too. This study provide a basis for further study of molecular mechanism.