ABSTRACT
<p><b>OBJECTIVE</b>This study was to explore the effect of arsenic trioxide (ATO; As(2)O(3)) on differentiation of chronic myeloid leukemia K562 cells and its potential mechanism.</p><p><b>METHODS</b>ATO with different concentration (0.1, 0.5, 1.0, 2.0, 5.0 µmol/L) were used to treat K562 cells, and MTT assay was used to detect the growth level of K562 cells; Benzidine staining was applied to measure the change of hemoglobin content; flow cytometry (FCM) was conducted to detect the expression of CD41 and GPA on K562 cells; RT-PCR and Western blot were used to measure the mRNA expression of BTG1 and TAL1 and the protein expression of BTG1 and TAL1, respectively.</p><p><b>RESULTS</b>ATO significantly inhibited the growth of K562 with dose- and time- dependent manners by benzidine staining, the positive rate of K562 cells induced by ATO reached to 17.63% ± 1.18%, which was significantly higher than that of control (2.87% ± 0.63%) (P < 0.01), and GPA, as the specific marker of erythroid cell differentiation, achieved 68.46% ± 3.67%, while it in control was 3.39% ± 0.84% (P < 0.01), besides, the CD41 expression of megakaryocyte increased but not so obvious as GPA. Meanwhile, the differentiation-related transcriptional factors TAL1 and BTG1 mRNA and the corresponding proteins were expressed more highly.</p><p><b>CONCLUSION</b>ATO can induce the differentiation of K562 cells into erythroid cells and megakaryocyte, which is associated with up-regulation of the related transcription factors TAL1 and BTG1.</p>