Guo W, Wang H, Zhao W, Qu B, Pan L, Zhu J, Chu H, Wang X
Shanghai Institute of Hematology, Ruijin Hospital, Shanghai Second Medical University, Shanghai 200025, China.
Zhonghua Xue Ye Xue Za Zhi. 2000 May;21(5):240-3.
To investigate molecular mechanism of tissue factor (TF) expression on acute promyelocytic leukemia cell line NB4 cells down-regulated by all-trans retinoic acid (ATRA) and arsenic trioxide (As(2)O(3)).
Cyclohexamide (CHX) inhibition test for de novo protein synthesis and actinomycin D (Act D) inhibition test for RNA synthesis were used to check the effect of ATRA on the TF expression. TF antigen of U937 cells transfected with pMSCV-PML-RARalpha treated with or without ATRA and As(2)O(3) was detected.
CHX treatment completely suppressed the down-regulation effect of ATRA on the TF mRNA expression, Act D inhibition test showed that half-life of TF mRNA in treated NB4 cells was shortened to about 30 min from that of around 60 min in untreated NB4 cells. The TF antigen contents in U937 cells transfected with pMSCV-PML-RARalpha were significantly higher than that in transfected U937 cells with retrovirus vector. Both ATRA and As(2)O(3) could down-regulate the TF antigen level in U937 cells transfected with or without PML-RARalpha.
The modulation of the TF mRNA expression in NB4 cells by ATRA might be indirect. TF mRNA destabilization was involved in the TF regulation process mediated by ATRA. Elevated TF antigen level in U937 cells transfected with pMSCV-PML-RARalpha may be related to the fusion protein PML-RARalpha. The down-regulation effect of ATRA and As(2)O(3) on the TF expression of U937 cells might not involve the fusion protein.
探讨全反式维甲酸（ATRA）和三氧化二砷（As₂O₃）下调急性早幼粒细胞白血病细胞系NB4细胞组织因子（TF）表达的分子机制。
用环己酰亚胺（CHX）抑制试验检测蛋白质从头合成，用放线菌素D（Act D）抑制试验检测RNA合成，以观察ATRA对TF表达的影响。检测经或未经ATRA和As₂O₃处理的转染pMSCV-PML-RARα的U937细胞的TF抗原。
CHX处理完全抑制了ATRA对TF mRNA表达的下调作用，Act D抑制试验显示，经处理的NB4细胞中TF mRNA的半衰期从未经处理的NB4细胞的约60分钟缩短至约30分钟。转染pMSCV-PML-RARα的U937细胞中的TF抗原含量显著高于转染逆转录病毒载体的U937细胞。ATRA和As₂O₃均可下调转染或未转染PML-RARα的U937细胞中的TF抗原水平。
ATRA对NB4细胞中TF mRNA表达的调节可能是间接的。TF mRNA的不稳定参与了ATRA介导的TF调节过程。转染pMSCV-PML-RARα的U937细胞中TF抗原水平升高可能与融合蛋白PML-RARα有关。ATRA和As₂O₃对U937细胞TF表达的下调作用可能不涉及融合蛋白。
