[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.

[Screening drugs for regulating tissue factor gene expression].

This study was purposed to screen the drugs for regulating tissue factor (TF) gene expression through establishing stable cell line with luciferase gene having TF promoter transcription activity, so as to provide the basis for further studying the molecular mechanism of screened drugs. A series of luciferase reporter gene plasmids under control of 5'-truncated TF promoter (including -2174 bp - +128 bp, -684 bp - +128 bp, -247 bp - +128 bp and -201 bp - +128 bp) were constructed. The above plasmids were separately electroporated into U937 cells to establish stably transfected sublines.

[Establishment of stable subline of K562 cells overexpressing high mobility group B1 protein].

This study was aimed to establish a stable subline of K562 cells (K562-HMGB1) overexpressing HMGB1 protein and K562-HMGB1 sublines served as control, so as to provide a basis for exploring the role of hmgb1 gene in occurrence and development of leukemia and their mechanism. Protein-coding gene of hmgb1 was amplified by PCR with cDNA as template, which was synthesized by reverse transcription from total RNA extracted from U937 cells. The PCR-amplified hmgb1 gene was ligated into PMD18-T vector (PMD18-T-HMGB1 vector), and then transformed into E.