[Expression of IRP2 mRNA, TfR mRNA and Fn mRNA in HL-60 cells].

To explore the mechanism of iron metabolism and its regulation as well as the roles of IRP_2 in ion metabolism of HL-60 cells, HL-60 cells were cultured in RPMI 1640 medium supplemented with 10% heat-inactivated fetal bovine serum,which was treated with ferric chloride (FeCl_3) or deferoxamine (DFO). The cells were harvested at 12, 24 and 48 hours of proliferation, and total RNA was isolated; cDNA was synthesized by reverse transcription (RT), and relative expression levels of IRP_2 mRNA, Fn mRNA and TfR mRNA were determined by RT-PCR. The results showed at follows: (1)the level of IRP_2mRNA remained constant in all cells, whether or not treated with DFO or FeCl_3. However, the expression of IRP_2 mRNA decreased when the time of cell culture was prolonged. There was no significant difference between groups (F_(B-S)=1199, P﹥0.05), but there was significant difference among the different time culture (F_(W-S)=43.418, P0.01). (2) Cells which treated neither with DFO nor ferri chloride showed significant difference from the control (F_(W-S)=7.184, F_(B-S)=113.926; P0.01). The level of TfR mRNA increased in the cells treated with DFO. Surprisingly, when cells treated with FeCl_3, there was not decline of TfR mRNA expression, but it increased lightly at 12 hours and peaked at 24 hours and declined drastically at 48 hours. (3) The level of Fn mRNA in the cells treated with FeCl_3 was approximately 2-fold as the control cells. In contrast with the control cells, there was significant difference (P 0.05). The level of Fn mRNA of the cells treated with DFO had little change. As compared with the control cells, no significant difference was seen (P﹥0.05). (4)There was not any significant correlation between IRP_2 mRNA and TfR mRNA or Fn mRNA in HL-60 cells (r=-0.005; r=0.074;P﹥0.05 ). It is concluded that (1) IRP_2 may regulate the iron metabolism in HL-60 cells by altering amounts of the IRP_2 3.7- or 6.4-kb mRNA at the transcriptional level,or by IRP_2 degradation at the post transcriptional level. (2)Both of Fn mRNA and TfR mRNA participated, more or less, in the iron metabolism in HL-60 cells.