ABSTRACT
This study was aimed to investigate the homeobox A9 (HOXA9) mRNA and protein expression in myeloid leukemia cell line HL-60 and effect of all-trans retinoic acid (ATRA 1 µmol/L) or arsenic trioxide (As2O3 1 µmol/L) on its expression, and to explore the pathogenesis of leukemia mediated by HOXA9 at mRNA and protein levels. The expression of HOXA9 mRNA and protein were detected by real-time fluorescent quantitative reverse transcription polymerase chain reaction (FQ-RT-PCR) and Western blot, respectively. HL-60 cells were divided into 3 group: normal control added with RPMI 1640 medium, ATRA group and As2O3 group. The results indicated that HOXA9 mRNA expression in each group showed a firstly increasing and then decreasing tendency, in which the expression of HOXA9 mRNA was observed at day 1, increased at day 2, and decreased at day 3; while HOXA9 protein expression in each group was observed at day 1, the expression of HOXA9 protein in control group and ATRA group showed firstly increase and then decrease. The expression of HOXA9 protein in As2O3 group showed a decreased tendency gradually. The expression of HOXA9 mRNA in ATRA groups at day 1-3 was higher than that in control group (P < 0.05). The differences of HOXA9 mRNA expression between As2O3 groups and the control group were not significant at day 1 and day 3, but was higher than that in control group at day 2 (P < 0.05). The expression of HOXA9 protein in ATRA group at day 1- day 3 was higher than that in control group (P < 0.05). Compared with control group, the expression of HOXA9 protein in As2O3 group was higher at day 1 (P < 0.05), lower at day 2 (P < 0.05), and no significant differences at day 3. It is concluded that HOXA9 mRNA and protein express in HL-60 cells. ATRA 1 µmol/L can up-regulate the expression of HOXA9 mRNA and protein in HL-60 cells. The mechanisms of treatment of leukemia by ATRA and As2O3 may be associated with the regulation of the HOXA9 mRNA or protein expression.